I'm doing a load of bathrooms at mo.
Tiny rooms, and yes I'm removing a block work wall, so I'd need to tack a bit of board in , but they're cracking, have been painted about a hundred times, so just better to overboard.
Thing I've found with bathrooms a d kitchens, is the ceilings tend to get painted in silk, gloss over the years. Landlord gets hoppo in to lash b and q emulsion over everything, so might look sound, but a disaster waiting to happen.
Had a kitchen a few months back. Had one hairline crack about 2 feet long.
Fussy customer, so I said i could do an invisible mend without re-skiming. Alsohad coving. Anyway, turns up, carefully removes the skim, about an inch either side of crack so I can scrim and easifil, then the skim started to flake off. Within minutes, I'd got about 2m of skim popped off on floor.
Had to remove coving, over board, skim, cove. Was flat out at the time, didn't really want the morning job to fill it, but they were chuffed in the end.
Found out after they'd had a leak from the bathroom about ten years earlier and the ceiling was re-skimmed on the insurance!