The Price of Peace
Experience is handled a wee bit differently here; the results should be approximately the same, but we eliminate a variable to make things a bit simpler. The eliminated variable is, in fact, XP.
Experience and wealth are both implicitly determined by the one real independent variable: encounters. Both are intended to scale according to the EL. If everything goes by the book, after roughly 14 encounters on average, a party of 4 has earned enough experience to advance to the next level and has accrued wealth on par with the Wealth by Level table.
Hence, experience is rather redundant; the same information can be determined by the party’s wealth. So, I keep track of the treasure the party has earned, and they level up at the end of any session where they’ve earned the cumulative wealth in gold according to WBL for the next level. This way, their power levels are approximately as recommended in the DMG. For example, at the end of Session II, the party had about 10000 gp from their adventures, well over the required 7200 gp for a party of four to reach level 3, so they leveled up.
Currently, the party has about 35000 gp toward the goal of 45000 gp to reach level 9.
(I say “about” and such because the characters technically don’t know the exact value of some of their treasure, but I still want the players to have a reasonable sense of how close they are to the next level.)
To be honest, I’m just using this as a guideline to keep the characters about on track for wealth, and the “level up threshold” is fuzzy and not immune to ad hoc story experience.