I had never heard of Dave Arneson's house rule for XP being awarded for gold spent (vs merely recovered from the dungeon) until I came across it while reading through old Grognardia posts.
The idea didn't do much for me at the time, however, so I just filed it away under, "interesting variants I'll probably never use."
carousing table -- essentially a way for players to gamble on blowing their wealth for even more XP. It was definitely a cute idea for a certain kind of campaign, but I didn't really see myself using it either.
Since I started running Dwimmermount, however, I decided to follow James Maliszewski's advice and give XP for gold spent a try ... but what exactly are the characters supposed to spend it on? I mean, how many warhorses can one guy collect? The expanded equipment list for 5th edition D&D will help a bit (once I multiply a few of the prices by 10), but even that will only go so far.
Recently though, the final piece dropped into place. Somewhere over the years ... maybe in GURPs? ... FASA's Shadowrun perhaps? ... I'd come across the notion of a character's economic lifestyle impacting their healing rate. Characters who lived wretchedly wouldn't recover at the same rate as those who could afford a luxurious lifestyle. That's a no-starter in 5th edition with its accelerated healing rates, but then I got to thinking ...
What if your lifestyle (modest, rich, opulent, princely), as established by your choice of when carousing, determines your minimum hit points when leveling up?
That way the players have a very compelling reason to risk a roll on the mishap table. A rich lifestyle, for instance, means that your lowest possible roll is a 2, whereas a princely level of indulgence assures that, even if the dice come up a 1, you'll add at least 4 hit points when leveling up.
Important to note -- this isn't a bonus, the maximum possible hit points gained remains the same, it simply represents an (expensive) insurance policy of sorts against bum rolls. And once they buy-in? The characters have to keep paying to maintain that benefit.