We’ve recently finished decorating a house and echo the comments above about using the right paint.
We had some fresh plaster to do, so used cheap own brand stuff watered down with water. We then used better quality paints for the final coats.
If you use cheap paint you’ll need to give walls/ceilings multiple coats…especially if the wall is not white to start with.
I had a lot of plaster repairs to do so used Easyfill for this (it gets easier with practice). For sanding that down I had a Makita random orbit sander. I’ve also got a black and decker sander, but I found that the fine dust meant that the sandpaper stopped sticking to the Velcro pad. The Makita sander has clips so it doesn’t rely on Velcro.
Painting a house takes forever…paying a professional is expensive due to the time spent. Since we finished someone told me you can get someone to spray paint the house which is cheaper as it’s quicker…haven’t really looked into it though, other than someone in the pub telling me about it.
Another tip…don’t leave masking tape for ages, it’ll take paint off when you remove it.
Also, if you do need to do lots of sanding of Easyfill…get a good mask, the dust gets everywhere,