I’m not sure who started it (though my guess is the Stew’s own Don Mappin), but my group has a longstanding rule that has served us well for years:
For the first adventure or two, or the first couple sessions (whatever’s appropriate to the current game), PCs can be reworked freely between sessions — you can change pretty much anything you like about your character. After that, they change and progress normally.
This has become part of our social contract (or a cross-system universal house rule, if you prefer), and one or more of us nearly always take advantage of it when we start a new game. We tend to play games for at least a year, sometimes longer, which represents a pretty good-sized commitment for everyone involved. Playing a character who turns out to be less fun than you initially thought for a year or longer isn’t enjoyable for anyone — the player of that character, the GM, or the other players at the table.
So for the first session or two, we always treat our characters as fuzzy outlines, sketches, or best guesses. If a character isn’t as tough as you’d hoped, you didn’t fully appreciate the ramifications of a particular rule, their personality and stats don’t line up, or you hate some aspect you expected to enjoy, you can change it. When the “no more changes” line is approaching, the GM gives us a heads-up: “After this session, you’re locked in.”
It works in part because no one sets out to abuse the system; my group isn’t wired that way. We trust each other, and we all want everyone at the table to have fun. This simple tweak, having a grace period for ill-considered or otherwise unwelcome character elements, has proven to be an easy way to head off one major cause of burnout, loss of interest, or other roadblocks to weekly fun before it becomes an issue.
If it sounds like a good fit for your group, give it a shot. If you’re already doing something like this, but perhaps implemented it a bit differently, tell us about it in the comments.