Personally, I think small numbers like this should be viewed as bad taste just like we’d deride sloppy character feel or unintelligible attack signalling.
My values are: each gear item should create a noticeable difference that can be used to adjust play patterns. If the benefit is too small, it’s not worth awarding the gear. Big level curves throw the biggest wrench in this – you need to say that the perks on a level 80 item are better than those on a level 10 item, so you want a differentiated curve, but that’s no excuse for making them pathetic at any point in the curve.
Generally I set out the maximum and minimum bounds – at what point does giving the player this value break the game, at what point is this pointless? – and then I double the minimum value bound.
This is also easier if you: are single-player (balance is only between choices the player can make, it’s not damaging others’ experience), are not giving them something in perpetuity (roguelikes can break balance and it’s a virtue because you shake the etch-a-sketch later), have explicit abilities to give the player rather than cheap, invisible number changes.
“More impactful, more discrete, more verb-y, at the expense of breadth” are my progression values.