Vows and Codes of Conduct [5e]

Tying game abilities to behavioral restrictions has always been a bumpy road, but I think the new rules provide some interesting options.

Consider a simple code of conduct for a monk or priest:

• No touching money (coins).
• No touching members of the opposite sex out of combat.

If you violate either of these strictures, you lose:

• You proficiency bonus
• Any unspent spell slots

Until your next Long Rest (which you must spend meditating and doing penance, but you can still regain spells as normal- you don't have time to do anything else, however).

Couple of points:

• Keep rules concrete and few in number
• Doesn't have long-term alignment impact- that is a different ball of wax
• Doesn't cripple you by removing all abilities, but is serious enough to not be used willy-nilly
• Restoration is low-impact, but not automatic (because you have to make it until your next safe spot for a long rest)

Likewise, you can take on optional strictures (like "no edged weapons" or "no metal armor"). Doing so gives you Inspiration at the end of the next Long Rest (provided that you didn't break a mandatory vow during the same period).