Wait, really?! I was under impression that Ring of Charm never worked somehow. Maybe it's some hidden change from 04ea4 or never, didn't had time to fully commit to these yet.
Yup, really.
I even managed to screw up and charm the mino blacksmith once. Was funny as hell seeing the trader and the smith following me around. It was only 40 turns or so, so when the charm wore off they immediately started moving towards the exit where their normal position was at.
I have no idea when it became a thing in the game, I only noticed it on 0.4. When the game was changed to allow you to keep all of your inventory, I started playing around with a few things and seeing if boosting a ring of charm did anything.
At about level 20 a ring of charm will charm anyone for something like 500-600 rounds.
A boosted ring of recharge is pretty disappointing, even at +14 I only get +1% recharge per turn.
A boosted tome of healing is awesome as fuck, it can heal Chloe and her allies for about +300 HP at lvl 15 or so.
A boosted Iron Hide tome is okay. At about +15 Chloe gains about +20 AC, but allies still only gain +3 for being a blessed book.
A detection tome is kind of meh. Boosted one to about +10 and all it did was increase the range, the duration was still the same.