get some 120 grit paper and give them a light sand over, dust shit and dust off them give them 2 coats of the paint you want to apply. you should always go over with 120 grit sand paper so that the new paint has a good surface to key on to

^ That's either vinyl or veneer (real wood finish).

is it wood, or a wood effect wrap over them like kitchen door fronts?

I'd buy Dulux satin wood paint..... just painted a radiator cover with this and really pleased with the outcome

Yes. You'll get a better finish cos as you said you've got a gloss on them and it will look better and be easier to paint on and shouldn't flake in a few months

Is it going to make a massive difference? theres 11 doors to do :|

You could paint over them but you would be better off rubbing them down.

theyre wood, not sure what type and have a gloss over the top

MOre info on the wardrobes. Are they pine? Chip board? What finish are they, gloss?

Basically, im decorating my room, ive done the walls but now have to do the wardrobes. Theyre built in. Is it possible to just paint over them? or do I have to sand them all down?