i dont generally, means featherin in and it never looks right, depends how big...we was on about 25m ceilings earlier and that is a pretty big ceiling 5mx5m or equivalent... thats about as bg as ill do on my own... any bigger than that and ill get another plasterer to help, doesnt have to be too skilled but it helps...
if you can get someone to either lay it on without too much mess or follow you flattening up (probably easier for you in the long run) you can put up to 50m on..
biggest ceiling i ever did wasnt too long ago 49square... 7mx7m bloody massive and two of us sweated on it.... took 5 bags...
ive heard people go on about 40m sets regular but that is 4 x 4m walls @ 2.4 high...
lot of skim to look after that is...