I'm wondering if this is common or something less widespread in DnD.

Cumulative skill checks, by my definition, are where you either require a string of successes or you need a large total to be added up over multiple tests.

They come into their own when time is of the essence - enemies are charging towards you, the room is filling with sand, that sort of thing.

For example: setting a lock to need a cumulative DC of 30. one person can take as many rounds as needed to roll a total of 30 on their checks - EG, rolling a 12, a 14, and then an 18 will unlock the lock on the third round. This means 3 rounds have passed and other things have happened.

This stops things from being all-or-nothing, as you can roll low on picking the lock for more rounds and still ultimately succeed. As such, it has no real place where there's no time limitations (just use the result rolled on one check to dictate how long it took) but it seems effective in time-trialled environments and during combat.

So, do you use them? have you heard of them before? Is this common as mud?

I tend to sway away from them as the more you ask for a check the more likely you move towards a failure. 

It depends highly on the check as well.....According to JC if you roll stealth and keep finding cover  you only ever have to roll stealth once to cover a great distance. Stealth is the one I feel like I  never quite do correctly. I tend to give the players the benefit though and lean towards success if I feel its earned (using resources/quick thinking to maintain stealth). 

Recounting information? One and done check. You are likely not going to recollect any new information.

Investigation?  Has any new information been obtained? If so you might have a chance to start linking ideas in your head. 

Perception? Factors constantly shift and if you are constantly on alert for new things particularly if you focus on a single direction I would likely allow it. 

Insight? Have they spent more time with the creature? If so they might get a new chance at insight.

Animal Handling? Depends on the creature. If they have a good memory they will not trust the person after a bad check.  A beast might be more forgiving with the right motivation (read food).

These are just some examples of how I do it but the fact you are thinking about it already means you are likely doing what you can to make the situation fun!

The nearest I have seen to this is multiple people are trying to accomplish a task.  For example a stone might be large enough for two people to try to lift and set a DC30 for their total score.

It is also common to have the party contributing to pass/fail skill checks for example after the party have found evidance the BBEG was recently where the party the party members can say how they would try to find him and must use different ability checks, one might attempt to climb a tree so see if there is any sign of him (DM might ask for athletics follwed by perception), one might look for tracks (survival) one might ask a passing dog owner if they can hire the dog to smell his trail (persuasion and animal handling), the DM can set the DC based on how hard they think the approach given by the player is and they might need to succeed on at least 3 out of 5. 

Past a point, rolling more dice won't significantly change the outcome. For example, rolling 5d20 with a cumulative DC of 50 won't be much different from rolling 10d20 with a cumulative DC of 100, but both will be a lot more consistent than rolling 1d20 with a DC of 10. But if you just want a more consistent result, I recommend the simplicity of a single ability check, but roll 2d10 instead of 1d20.

I do think a sequence of cumulative checks can create an exciting story moment. You can have the rogue spending their turns attempting to pick the lock, while the rest of the party might use their turns trying things to prevent the ceiling from lowering.

And yeah, using a party ability check for lifting something heavy makes more sense than the official rules, which would allow you to use the modifier of the strongest PC with advantage from help from the weakest one. It also discourages dump stats, since having one party member with a high score in each of the stats won't get you out of every situation.

Here is a rule that would work as an equivalent in my mind. 

Multiple Ability Checks

Sometimes a character fails an ability check and wants to try again. In some cases, a character is free to do so; the only real cost is the time it takes. With enough attempts and enough time, a character should eventually succeed at the task. To speed things up, assume that a character spending ten times the normal amount of time needed to complete a task automatically succeeds at that task. However, no amount of repeating the check allows a character to turn an impossible task into a successful one.

In other cases, failing an ability check makes it impossible to make the same check to do the same thing again. For example, a rogue might try to trick a town guard into thinking the adventurers are undercover agents of the king. If the rogue loses a contest of Charisma (Deception) against the guard’s Wisdom (Insight), the same lie told again won’t work. The characters can come up with a different way to get past the guard or try the check again against another guard at a different gate. But you might decide that the initial failure makes those checks more difficult to pull off.

Setting a high DC that adds up with cumulative checks isn't much different than a allowing multiple checks to beat a high DC once. For example, if a Rogue's average  lockpicking roll was 15, you would expect a DC 45 cumulative check would take 3 tries on average( high and low rolls taking less or more tries, respectively). Alternatively, you could set the DC to a number that the Rogue can only roll about 1/3 of the time and get a somewhat similar mechanic.

The only real question for me is, does all this rolling add value? Could a character simply say: "I'm spending a minute with this lock mechanism", while the rest of the party performs their own activities? The last example being purely narrative and quick instead of requiring multiple ability checks. 

The only time this adds to the game is when you have a ticking clock - as I said in the OP, like when the ceiling slowering or the room is filling, and the task is a complicated one. Picking the lock to a door behind you whilst a large pack of wargs close in, for example. Basically, the mechanic is there to make something take longer, without making it just a game of fishing for numbers. If you give a lock a DC of 45, and the rogue an average roll of 15, then you expect it to take 3 turns on average, maybe 4, but never less than 2. It's a mechanic for drawing out the game a little, so a player doesn't disperse any tension by simply rolling high on a single skill check.

I had to like both ThorukDuckSlayer post #6 and BigLizard post #7 because, they both make excellent points and further prove that it depends on what you are trying to accomplish doing(or avoid doing) that will dictate what type of ability check determination methods you will use as a DM.

Quote from ThorukDuckSlayer >>

The only time this adds to the game is when you have a ticking clock - as I said in the OP, like when the ceiling slowering or the room is filling, and the task is a complicated one. Picking the lock to a door behind you whilst a large pack of wargs close in, for example. Basically, the mechanic is there to make something take longer, without making it just a game of fishing for numbers. If you give a lock a DC of 45, and the rogue an average roll of 15, then you expect it to take 3 turns on average, maybe 4, but never less than 2. It's a mechanic for drawing out the game a little, so a player doesn't disperse any tension by simply rolling high on a single skill check.

 You can do this in a less tedious manner by requiring different checks rather than X number of lock-picking checks which engages the rogue but leaves everyone else just sitting around.

The door also have a magical field surrounding it. It's got sliding tiles that require an investigation/intelligence check to figure out. Once unlocked, it's still stuck fast and needs to be shoved open, etc. In other words, a skill challenge (which I personally think is a great mechanic that is only detrimental to roleplaying if you're doing it wrong).

If the roll doesn't determine success or failure, I'd rather it just determine how long something takes directly. Roll 15, takes 4 rounds; roll 20, takes 3 rounds; and so on - something like that. That way the party can still decide to abandon ship halfway though if they want, or push their luck if they're willing to deal with what might be coming.  

Quote from pangurjan >>

If the roll doesn't determine success or failure, I'd rather it just determine how long something takes directly. Roll 15, takes 4 rounds; roll 20, takes 3 rounds; and so on - something like that. That way the party can still decide to abandon ship halfway though if they want, or push their luck if they're willing to deal with what might be coming.  

This is also a fair approach with time factor being the complication for "failure" 

I don't use this mechanism since you can get similar results by allowing multiple attempts - including failure to succeed within the time frame of the encounter.

I could see using this if you wanted to increase the chance of success within an average time frame and eventually guarantee success but did not want the character to succeed on the first attempt.

e.g. for a rogue with a lock picking modifier of +8, setting the DC at 29 means that it will take a minimum of 2 rounds but no more than 4 to succeed at the task. On the other hand setting a DC of 24 in this case gives a 25% chance of success on every round. This is a 25% chance of success in the first round and about 70% chance of success somewhere in the first 4 rounds overall.

One problem with this though is that the rogue who rolls 20 in the first round and fails, may find themselves succeeding when they roll a 1 on the next round which is somewhat counter intuitive.

P.S. I think you meant to use "Nay" in the topic title. "Neigh" is the sound a horse makes ...

Quote from David42 >>

I don't use this mechanism since you can get similar results by allowing multiple attempts - including failure to succeed within the time frame of the encounter.

Not every check should allow for a retry - picking a lock, probably; hiding in order to ambush an enemy, probably not - and multiple attempts can, if the dice just aren't helping out that session, become a tedious affair of repeated failure until the DM just decides that the previous 15 attempts apparently softened up the obstacle and your 16th one succeeds regardless of the roll or that the first 15 attempts jammed the obstacle beyond repair and there's no point in continuing to try. Go with whatever works for you and more power to you, but for me that's not a good way to go about things. If ultimate success is not really in doubt I prefer not requiring a roll at all, and if it's a matter of timing I don't want poor luck to result in the players potentially making a dozen rolls for something that can pretty much just as well be determined with one. 

I don’t do large DCs but I do have a large egg timer that sometimes I put up on the table, turn over and then present a series of challenges, the players have to think fast and react and make appropriate skill checks for what they want to do. Failing a single check will just increase the DC of the next, while success makes future progress easier. 

I might also present a series of skill checks to complete some task, forging a magical weapon to beat the BBEG for instance,