How do you handle Wish?

[RSP]

I never said slippery slope, I just said I would not allow it. Boons are a variant rule that I have never used. If a player wished for a boon, I would allow it, but which boon would have to be consistent with the PC's deity.

A one time use of a d30 is a crappy wish and a waste of a 9th level slot and a further waste of a spell that the PC may lose forever (33%).

I guess you just miss my point entirely that a wish in the game should not be a wish in real life. But if you're willing to give your car to a player that wishes for it, that is your issue.

I still don’t see how an extra 9th level slot isn’t in-game. Do you operate that casters are unaware of the level of spells, or of how their energy to cast spells (spell slots) are cut out to only work in certain power levels?

If you use Spell Points, it would be different, but you’d still have in-game characters aware of spell levels and, I’m assuming, that they can only cast one level 6, one level 7, one level 8 and one level 9 spell.

I just don’t see how it isn’t an in-game thing to realize you can only cast a 9th level spell once a day, or wishing that you could instead cast that highest level of spell power twice instead of once.