Tradable XP.

[SangoProduction]

So, I had set up a sorta system where, instead of xp just being some invisible force that makes you better at cooking when you rip monsters' heads off, to instead be a gem that's composed of condensed memories and knowledge....and only drops from monsters from a particular place. Thus, story wise, it's essentially a "risk you life, but get good really, really fast," sorta thing. As in you could be a master chef...if you spent decades being a chef...or a couple weeks killing some monsters.

I did intend for this to end up with people selling the xp, or even dumping the xp in to a single person. However, I ended up allowing downtime rules, because I didn't really find anything too offensive.

And then the players started talking about using the downtime rules for generating xp by dumping the xp on to one person. I did not notice that.

Kinda goes against the intent and design of the system. Downtime xp is also intended to allow people who missed xp opportunities (such as by missing a session) to catch up, because normally xp is distributed evenly. So this use also goes against the intent of the downtime system. Not to mention earning xp by playing spreadsheet simulator, while fun for some, it's definitely not fun for me as I watch YouTube waiting for them to finish up their calculations, rather than engaging in any sort of gameplay.

So I am feeling like I should disallow that. But I already said I'd allow downtime rules, and I think I got them thinking the wrong thing.

Should I go ahead and allow it anyway, and just own up to the mistake? Or should I tell them not to do it?

[Quarian Rex]

Downtime rules are fine. Just take out the 'Earn Xp' option as it is now redundant. That was a kludgy fix for a problem you no longer have since the players can just have a character that has fallen behind use some of their stored xp.

You have made an interesting change in your campaign, one that has empowered the players more than anything else. Don't be afraid to adjust things to compensate. Adding back xp costs to spells and crafting (assuming that you are playing Pathfinder) is now completely viable since the burden is no longer being born by a single character. Even actual level loss is now playable since the players have an actual recovery mechanic, making it a costly penalty but not one that hinders the actual game.

The players now have many more option but so do you.

[unseenmage]

Are you aware of the Transference (http://archive.wizards.com/default.asp?x=dnd/we/20060526a) spell?
With it xp was already fungible.

[StSword]

The World of Prime setting for dnd basically had those rules.

Experience was harvest residual soul energy left behind by dead things.

After harvesting it, one could then use it to make magic items, ingest it to gain levels, or give/trade/sell it away.
residual Soul Energy however was the only way to gain experience, though.

Or feed it to creatures, either to just advance their hit dice, or make monsters by feeding them specific residual soul energy. Feed a lion a lot of eagle exp and eventually you'd get a griffon.

I particularly was intrigued with the premise that all class benefits are magical superpowers, though.

The fact that you could shoot a twentieth level wizard in the face with a cannon and it would be a mere flesh wound? Magic superpower. The fact that a high level rogue can dodge things like they're in bullet time from the Matrix? Magic superpower.