BUY GOOD BRUSHES!
That's the best advice I ever got. Purdy brand brushes are expensive, but fantastic. With a steady hand and a GOOD brush, there's no need to tape unless, like me, you don't want to lie on the floor to do the bottom trim. I know younger, more nimble ones will not have a problem!
OK, here I have to sort of dissagree. We just painted our rental trailer and I got some of my friends to come help out.. we painted the entire 2 bedroom trailer in a coat of oil based primer in about 6 hours.
We only used oil based primer because we painted over the top of old wall paper (water based primer would melt the wallpaper glue and cause it to fall off) .. if you are going on top of existing painted walls and the colour is similar you won't need any kind of primer.
If you are painting a pale yellow over say a dark red paint, you will need a WATER based primer... Oil based primers are just NASTY!
Anyway.. Get yourself to harbor freight. They have great brushes and the 1.5" wide ones cost like 45 cents each.. So cheap its not even worth cleaning them.. just throw them away.
Buy a couple of rollers and trays. For a pole simply unscrew the handle from your floor broom and it will screw straight into the roller handle.
For THICK ceiling popcorn get a thick nap roller.. You won't need to spray as long as the nap is thick enough. If the nap is not thick enough it will be brutal.. HF does not have particularly thick nap rollers (but their standard rollers are like a dollar each!) but any roller from Home Depot will fit the HF roller frame.
If you have carpet or any other surface you don't want to get paint on buy a big roll of "painters plastic" ($20 from Home Depot) and tape it to the top of the skirting boards.
Blue tape from harbor Freight as well.
Tape can get very expensive so consider using an edger as mentioned above.
Most cost can be saved by using a single colour and buying a 5 gallon pail of it... White for the ceilings and a coffee cream for the walls...:)
Have fun.. this is an easy job edging takes FAR longer than doing the rollering of the big surfaces.
Remove all swic=tch and outlet covers.. use a flat driver bit in a battery drill... MUCH quicker.
Frank