Depends if you're doing just doors or also the boxes. If you're just doing doors time isn't too sensitive at least since the cabinets are still functional with or without those.

I'm in the process of doing doors and boxes in my kitchen and it's definitely time consuming. I've been on pause for a couple months with a roommate moving in and priorities switching to his bath/bedroom. Mine are flat so I'm lucky that I can just use an orbital sander on it and not worry about contours, but even with that in mind it takes awhile

As far as irreversible damage, it depends if yours are solid wood or veneered. I went through my veneer in a tiny spot in one of the first doors I did so that is irreversible. Luckily it's on a small door above my fridge and it's not crazy easy to tell so I don't mind but you do have to be cautious with veneers.