Yup. Auto-sell everything except 6* epic/legendary, and auto-sell any flat stat glove/chest/boot. Also auto-sell mismatches, like DEF% on an ATK set, etc...

I'm not even mid-game and I'm selling anything that isn't 5* or up, with the exception of accessories and special reward kind of gear.

Speaking of which, I'll hijack the thread a bit and ask; are there any sets that I should just sell regardless? So far I haven't bothered saving any curing sets, and I feel like the toxic and cursed sets are also pretty pointless when I already have champions that can place 5% poison and 100% heal reduction.

WRT item sets, I don't sell any outright just because i don't know if they'll change them in the future to be better, but -

Situationally usable:

Destroy - really only need at most one champ with this set for scarab, if you have no other max-hp damagers.

Fury - personally haven't found a use for it, although I'm sure there are some specific champs that benefit

Curing - same as above, I guess technically on a dedicated healer like Scyl this might be useful, but I haven't really found any use for it

Reflex - very situational, for champs that absolutely want to be using a specific ability as often as possible

Immunity / Untouchable - could be useful on specific arena teams, but I really haven't found any that would prefer this over basically anything else

Regeneration - maybe some sort of weird cheese arena team with super high defense/resist and these items to stay alive, but since regeneration only triggers on your turn, i just don't see this working

Can't think of any use:

Cursed - technically I suppose it could be useful in a very specific arena team, but honestly, I find you're better off just killing them outright instead of trying something weird like this

Toxic - if it were 5% instead of 2.5%, I could see this having some use for certain CB teams, but at 2.5% i just don't see a use

Daze - this does have a higher chance to land than stun, but given it gets removed on damage I just don't see any reason to use this over stun

Pretty much. 5* speed boots are auto sell unless I triple proc Acc or something. I also sometimes keep some 5* legendary pieces if all the substats are good, then I'll roll it and see if it's really worth keeping. When I'm spring cleaning gear myself, I try to avoid the "maybes" as much as possible, and I'd remind myself that I'd have used this piece by now if it was actually good enough.