I just unlocked my second return slot (finally beat Bloodmage Gold!), and I'm not sure what to spend it on. My first return slot I used for Pendant of Mana -- because going from 13 max mana to 15 isn't usually a super important breakpoint, so I ended up feeling it wasn't usually worth the gold cost and inventory space.
There are items I rarely buy, like Troll Heart, Bloody Sigil, and Pendant of Health. But I've only been playing for a couple of months, and I'm worried that by banning out the items that I don't use much, I'll be limiting my ability to learn. Like, a friend pointed out that Bloody Sigil gives a ton of conversion value for very little gold, so I should probably be taking advantage of that more often. And Pendant of Health seems really strong in the earlygame. And if you buy Troll Heart early and convert it later, you're getting a bunch of health at no inventory cost. (I never really took advantage of that because never wanted to convert items I'd spent money on if I could help it, because I wanted to get the gold back at the end of the dungeon.) So maybe vetoing the basic items I don't usually lose will just limit me?
The only item I think I truly never buy is Stone Sigil, but that spawns so rarely already that vetoing it wouldn't do all that much. Maybe I should just start using my return slots on all the basic items (except the really good ones like Fine Sword) until I'm basically getting the Quest Items preparation every game for free?
More experienced players, what do you do with your return slots?