How many sessions to UP one level?

After nearly 4 decades of D&D, one thing I have realized is that the best D&D is usually somewhere between the beginning and the middle levels.  There have been some unique exceptions throughout the editions however that altered things.  1st and 2nd edition had a natural progression because XP was not unified, so characters didn't level up at the same time.  3rd edition you had prestige classes and players really wanted them so you sort of expedited them there and then played at that level for a long time as this was the sweet spot for the game.  4th edition was an unwieldy game after around 7th level (too many powers to track).  5th edition players want their Sub-Class ASAP so you are pretty much expediting to 3rd level and the game is best between like 3rd and about 12th level.  After that it gets very unwieldy and becomes a kind of gonzo fantasy where everything is solved with magic.

1st to 3rd level: 2-3 sessions per level

4th to 12th: Progressively slower, essentially its Level + 2 Sessions for each level.. so 6 sessions for 4, 7 sessions for 5 etc..etc..

13th to 20th:  If you play at these levels I speed it up.  I usually do 3-4 sessions per level from 13th level and sort of race to the finish with 20th level being like 1-2 sessions max for a finale to the campaign, though in fairness most campaigns end by 13th level.

Would be nice to be able to have some kind of session length selection, since I usually let my players level up after around 2 sessions. We do often run 6-8 hour sessions though, so that would be the same as a group that runs 3-4 sessions levelling up every 4 sessions.

Quote from theologyofbagels >>

Quote from Garr_Feyld >>

Im a slow leveller. They go up a level after they demonstrate mastery of their current level AND pass a test like complete an adventure milestone or defeat a miniboss. Also people gotta do something super significant to go up a tier.

I'm a level Scrooge lol. My players seem to enjoy it tho.

 This is how I run my games, too. My campaign also happens to be a bit of a slow burn intrigue thing, and our sessions only last three hours. We've played for exactly two years today, and they've gone from level 4 to level 10. Weekly games. 

The slower pace suits my table well, and because level ups are relatively rare, everyone gets really excited when it happens. Sweeter payoff, in a way.

Same!! But I think I might actually run it even slower (although I'm not sure I am the one in control lol). My longest campaign has been running for over two years and my players are level 6 now. That being said, they reached level 6 when they arrived at this new town, and uncharacteristically zoomed through a lot of what the town had to offer... Only to then settle in the inn and spend 6 sessions role-playing in and around it (occasionally trickling out one at a time to check on this or go buy that) - All within the same 24 hours in-game, mind you!

Next weekend we are about to get into session 7, still in that same inn, without accomplishing any tasks, missions, combat encounters or significant social interactions - not really utilizing much of their new (6th level) abilities... So I don't feel it right to level them up in this circumstance. They have a mission, and they have been taking their sweet time avoiding it or any recon or research on it.
To be fair, I don't think they are avoiding it, per se. I think we all got caught up in a very touching character arc, and they all want to explore it fully. They seem to have fun just messing around with the scenarios they themselves create, so I let them enjoy it.
I've presented them with opportunities to both research in preparation for the mission or to take immediate action with supportive characters (or alternatively, without the support if they don't want it). And that is why I say I don't think it's in my control.
I can attempt to forcefully nudge them forward, but I've already done that a few times, and honestly it seems they all have more fun stretching things out, so I don't really want to get in the way of my friends having fun.

I have just undertook another campaign group, so I am curious to see how fast or slow those sessions are going to go.

Depends heavily on the intensity of the session.

A session where the party advances the story through investigative work or combat is worth something for advancement. A session where they go shopping, do roleplay, or instigate a murderhobo rampage (which isn't related to the story) won't be worth much for advancement.

I aim for milestones, and like to make it feel significant. I tend toward a milestone-esque XP based one, where I use the XP the party is gaining in combats as a rough guideline for when they are due a milestone. Then, I will plan in a milestone to make the level-up seem epic and earnt, like a miniboss or a big leap in the story!

I usually level up my players to level 2 ASAP so I don't end up killing them on accident. Otherwise, I level up at around 5 sessions and slower on from there. i think it's better to let players really get into their current level before leveling them up, so they don't get flooded with abilities.

Quote from imalius >>

Apparently the the baseline design of 5e is:

1 session Level 2

2 sessions Level 3

4 sessions Level 4

7 sessions Level 5

10 sessions Level 6

13 sessions Level 7

16 sessions Level 8

19 sessions Level 9

22 sessions Level 10

25 sessions Level 11

27 sessions Level 12

29 sessions Level 13

31 sessions Level 14

33 sessions Level 15

35 sessions Level 16

37 sessions Level 17

39 sessions Level 18

41 sessions Level 19

43 sessions Level 20

This will be helpful to me. I have been trying to figure out when my players will hit level 4.

If I'm using XP leveling, then my players are just mowing through the monsters to get it. There's probably a level up every 2 sessions or so.