Who let's them breathe, and who keeps them MOC?

I open all my figures. I couldn't possibly have as many as I do if I kept them MOC...I just don't have the space.
The only figure I've kept in the packaging is the Slim Jim Macho Man, but even that I took out of the outer sleeve.
I display is in the windowbox because it's perfect.

I open all my wrestling figures except autographed ones and a B16 Ultimate Warrior.

I’ve got double of some RSEs and Defining Moments. I keep AEW sealed because I get so few. I’ve got some box sets like FoF, UE, and Booty-Os. Jeff and HHH and Rock n Sock. I’ve got some Ultimate Editions sealed because I like all the stuff in the package next to them (80%would get toted and never seen). I’ve got some Bayley, Daniel Bryan, Undertaker, and Kane’s sealed. Entrance greats HBK and SDCC Undertaker.

Normal sets change too often, but I like keeping the exclusives with cool packaging or grabbing an extra if I can

I keep my ultimates boxed up

Both.
Although I’m opening less and less these days because my son won’t play with them anymore so they just would go into a bucket anyways.

All of my Mattel Legends are open, except for a L5 Macho Man, DM1 Macho Man, HOF Eddie, L8 Warrior and Eddie, and the Chase versions of Valentine, Rude, Roberts, Dibiase.

Golden Era WWF collector (1985-1992). I open Mattel figures unless there is a chance of getting them signed. Only collect Jakks figures if they are or can be signed. All Hasbro/LJN purchased on card stay that way.

I have three moc. Raw Metal Kane signed, LJN bendie Corporal Kirchner and BCA Blue Blazer. The Latter two are moc because my brother said to leave them that way. Otherwise I open everything. I much prefer having lose figures to display and pose. I don't buy for the intention of selling, so keeping them in the box has no use.

I let 'em breathe...I couldn't imagine how much room they'd take up otherwise. But I do have a small MOC collection.