For those who want to take life juuuust a little slower.
This mod raises the amount of exp required to level up for the Player Character and all Partners. There are multiple versions:
Version 1.120 multiplies the required amount of exp to level up by approximately 1.72
Version 1.140 multiplies the required amount of exp to level up by approximately 2.74
Version 1.200 multiplies the required amount of exp to level up by 8.
(Yes, that means even Version 1.120 almost doubles the exp required to level-up.
I would strongly suggest not using Version 1.200.)
Note that this mod is not compatible with my other mod, "Better Partners." I do, however, have a combined version of this mod, that provides both slower leveling and better partners - you can find it hidden here.
This mod should be completely save-safe to uninstall - the exp required for level-up is recalculated upon leveling up, so just reach the next level and things should go back to normal.