I have given this as a reply in a few threads, but I thought I'd start it as a topic of its own.
Some people are dissatisfied with the variability of standard 5e ability checks. Sometimes the 19 Str barbarian is unable to break down the door, but the 8 Str halfling succeeds.
Generally speaking, rolling more dice produces a more consistent result. Advantage and disadvantage are one way to roll more dice. Rolling 1d20, you have a 1/20 chance to roll a natural 1. But rolling with advantage, you have a 1/400 chance. Your die roll will be > 10 3/4 of the time. Or with disadvantage, you will roll <= 10 3/4 of the time. But how to make it most likely to roll close to 10? You could roll 2d20 and take the average, but now you have to do division, which is most people's least favorite arithmetic operator.
Instead roll 2d10. The average is almost the same. The average roll on 1d20 is 10.5, vs. an average of 11 for 2d10. So you don't really need to change DCs. But 2d10 is much more consistent than 1d20. 1 is impossible on 2d10. The probability of 2 or 20 on 1d20 is 1/20, whereas the probability of 2 or 20 on 2d10 is 1/100: you have to roll snake eyes or double 10s. The probability of 11 on 1d20, like any other number, is again 1/20. The probability of 11 on 2d10 is 1/10: more probable than any other result.
Here are all of the probabilities out of 100.
Total
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1d20
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
Total
0
1
2
3
4
5
6
7
8
9
10
9
8
7
6
5
4
3
2
1
As you can see, the odds of rolling close to 11 are much higher than the odds of rolling close to 2 or 20. The cumulative odds for rolling between 6 and 15 is 3/4, same as for rolling <=10 with disadvantage or > 10 with advantage.
You might choose to give consistent checks to any character with proficiency. Or you might use them for whenever the game situation gives the character a lot of control over the situation. For example, a Stealth check to hide suddenly when you hear an enemy approaching might be 1d20, whereas a Stealth check to infiltrate an area with advanced planning might be a consistent check with 2d10. Int checks like Arcana and History might be more consistent than Nature and Religion, the wilds and the gods being more unpredictable. Performance would be consistent if you have a rehearsal, but Deception must often be off the cuff. Saves are probably never consistent.
You could use 2d10 for attack rolls, but I don't recommend it. Combat, by its nature, already has multiple die rolls, and they tend to average out. If you use consistent 2d10 rolls for attack rolls, it's likely to result in almost never hitting or almost always hitting, depending on your attack modifier and the target's AC. It will tend to result in battles that are either trivial or unwinnable. Combat is already consistent enough, and making it more consistent just removes excitement. Whereas whole plot twists can sometimes hinge on a single ability check. Making them a little more consistent can avoid the frustration of your whole plan going awry because of one die roll.
Another reason not to use 2d10 for combat is that crits are impossible or almost impossible. 1 is impossible, but you could count 2 (snake eyes) as a crit fail. Still the odds are only 1/100, the same as a critical hit with double 10s. But if you like things to be consistent, I guess crits wouldn't be your thing. I think most players enjoy crits as a factor in combat, though. Again, since there are already so many die rolls in combat with multiple players and monsters and rounds, one or two crits probably aren't going to tip the whole battle (although it can feel like it).
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I have given this as a reply in a few threads, but I thought I'd start it as a topic of its own.
Some people are dissatisfied with the variability of standard 5e ability checks. Sometimes the 19 Str barbarian is unable to break down the door, but the 8 Str halfling succeeds.
Generally speaking, rolling more dice produces a more consistent result. Advantage and disadvantage are one way to roll more dice. Rolling 1d20, you have a 1/20 chance to roll a natural 1. But rolling with advantage, you have a 1/400 chance. Your die roll will be > 10 3/4 of the time. Or with disadvantage, you will roll <= 10 3/4 of the time. But how to make it most likely to roll close to 10? You could roll 2d20 and take the average, but now you have to do division, which is most people's least favorite arithmetic operator.
Instead roll 2d10. The average is almost the same. The average roll on 1d20 is 10.5, vs. an average of 11 for 2d10. So you don't really need to change DCs. But 2d10 is much more consistent than 1d20. 1 is impossible on 2d10. The probability of 2 or 20 on 1d20 is 1/20, whereas the probability of 2 or 20 on 2d10 is 1/100: you have to roll snake eyes or double 10s. The probability of 11 on 1d20, like any other number, is again 1/20. The probability of 11 on 2d10 is 1/10: more probable than any other result.
Here are all of the probabilities out of 100.
As you can see, the odds of rolling close to 11 are much higher than the odds of rolling close to 2 or 20. The cumulative odds for rolling between 6 and 15 is 3/4, same as for rolling <=10 with disadvantage or > 10 with advantage.
You might choose to give consistent checks to any character with proficiency. Or you might use them for whenever the game situation gives the character a lot of control over the situation. For example, a Stealth check to hide suddenly when you hear an enemy approaching might be 1d20, whereas a Stealth check to infiltrate an area with advanced planning might be a consistent check with 2d10. Int checks like Arcana and History might be more consistent than Nature and Religion, the wilds and the gods being more unpredictable. Performance would be consistent if you have a rehearsal, but Deception must often be off the cuff. Saves are probably never consistent.
You could use 2d10 for attack rolls, but I don't recommend it. Combat, by its nature, already has multiple die rolls, and they tend to average out. If you use consistent 2d10 rolls for attack rolls, it's likely to result in almost never hitting or almost always hitting, depending on your attack modifier and the target's AC. It will tend to result in battles that are either trivial or unwinnable. Combat is already consistent enough, and making it more consistent just removes excitement. Whereas whole plot twists can sometimes hinge on a single ability check. Making them a little more consistent can avoid the frustration of your whole plan going awry because of one die roll.
Another reason not to use 2d10 for combat is that crits are impossible or almost impossible. 1 is impossible, but you could count 2 (snake eyes) as a crit fail. Still the odds are only 1/100, the same as a critical hit with double 10s. But if you like things to be consistent, I guess crits wouldn't be your thing. I think most players enjoy crits as a factor in combat, though. Again, since there are already so many die rolls in combat with multiple players and monsters and rounds, one or two crits probably aren't going to tip the whole battle (although it can feel like it).