This brief post is for Kosherbacon who requested some clarity about why the player characters seem to be leveling so slowly.
The above screenshot is from a spreadsheet I use to place treasure in an adventure location. If you embiggen the picture you can see there are fields to type in the xp/char and the number of characters. This spreadsheet is included in my DM's Familiar, which you have access to through this site.
So for example, if your players were all roughly 3rd level we could say that (ballparking) 4,000 xp would lift them most of the way to 4th (using the fighter as the baseline). If you put 4,000 xp into the first field and 4 characters in the next field, you see that a treasure budget of 16,000 GP is generated for the dungeon. This means that if a party of 4 characters finds every single coin, some of them will gain enough xp to level and some (like magic-users and rangers) will get CLOSE to leveling.
So, you have to decide how many times a dungeon will level the PCs within a range and plan your budget from there.
Will the dungeon level a group of 3-5th level characters three times? What if there are 8 characters? What if there are 10? Bringing more characters should necessarily increase safety but diminish xp rewards.
Obviously monsters are not included in this calculation and I (personally) don't count them. Monsters are gravy. If a monster is vanquished the XP is a consolation prize for the resources expended.
Therefore, when I create a dungeon I do the following:
Tally the number of characters likely to attempt the dungeon (in my case this is usually 6+)
What are the levels of those characters?
What is the number of XP required to elevate one of those characters (on average) to next level?
A very small dungeon might have a budget of 1/4th or 1/2 of a level in terms of treasure.
A medium size dungeon might have a budget of 1 or 2 levels.
A huge dungeon might have a budget that can take characters from level 1 or 2 all the way to 9.
It is safe to assume your players will not find every coin. Therefore, your budget should have padding. Nevertheless, treasure should be sprinkled with the bulk reserved for locations that demand expert play and problem solving. It's ok for timid and unimaginative player characters to leave a dungeon badly wounded and with no real loot to speak of. This is the founding principle of D&D.
That said, most published adventures are far too light on loot. If your players have been clever but unlucky add a diamond ring to the treasure in the room they just cleared. You are the DM. That is your job, your prerogative and your responsibility.
If I were to make a dungeon for 1st through 4th level characters my treasure budget would look like this:
1--2 (2K per char)
2--3 (3K per char)
3--4 (5K per char)
This means a total of 10K in treasure per PC. Now I probably multiply this by 1.5 to pad the dungeon out and allow for the party to miss various locations or secret troves. This puts us 15K per character and I wouldn't hesitate to go to 20K per character if the dungeon is tricky with plenty of secrets.
Then I multiply 15K by 6 player characters.
90,000 GP is the budget for the dungeon. If the players bring more than six characters they level less. If they bring fewer they level more. Note that this 90K includes magic items. It does not include monsters.
If you think 90K GP is too high for a dungeon of this level range I'd advise you to reconsider. As long as you are taxing PCs, charging them for housing, sages, identification, training and so on you have little to fear. I've been doing this for 10 years now and the numbers work.
Just don't forget that you can throw the party a bone whenever you want and you can also bring calamity if needed. Easy come, easy go.
Peace and happy gaming.