Seriously now, how important is it to PRIME before you paint?

If your walls were already painted, you probably did not need to prime. If it was new drywall then priming helps to minimize the absorption between the mud areas and the bare drywall(a persistent problem in new construction).If it was new bare plaster than the need to prime is to cover "hot spots" in the plaster,which are areas that are higher in alkaline (I've seen this happen to a home owner when he paint his own new home, he paid me to correct it).These are the main reasons to prime :

1) stained surfaces(smoke,grease,water etc)

2)glossy surfaces

3)bare wood

4)bare metal

5) new plaster

6) new drywall

7)new assorted building products

8)hiding drastic color changes involving problem colors

9)to allow dark reds to cover

10) chalky surfaces

Primer is much more important if you are changing colors drastically or painting a bare surface. If the surface has never been painted before, the primer will penetrate the surface and give the finish coat a surface much easier to adhere to. Finish paint will merely sit on the surface and can chip. In your case, with the walls already painted and if they are not a glossy finish, you most likely will be fine with just the finish paint. Best to wash the wall down first but if you've already painted, I wouldn't worry about it unless it also was a glossy oil finish you were covering.

Ive never primed my walls ever. And I have lived in this house for 16 years, and have painted rooms over many times. The only thing you might want to prime would be wood trim if you plan on painting over them, that helps make sure the paint will stick to the wood, and also you might prime walls if you plan on putting up full sheets of wallpaper...

good luck,

from a lady DIY'er

It all depends on what's underneath. I'm assuming your living room walls already HAD paint on them. So if you had latex paint on there you dont need to prime in order to add more latex. Get it? You need to prime over regular wallboard (PVA primer) or bare wood or what not. Not if its already painted.

People also often prime with KILLZ or a similar primer if they had dark paint or stains that might bleed through the new paint.

you may not need to prime if you paint over painted previously surface. Old paint act as a primer. On new walls you need primer because paint will soak unevenly into the wall. Primer is to prevent soaking in.

I think it is because primer stickes better to a wall than paint. Then the paint stickes better to primer than to another coat of paint. Primers are more ore less flat and that gives paint a surface for the paint to grip onto.

priming is good for like the first paint on drywall. Or painting over oil based paint. Or lighter color over darker.

PRIMING BEFORE PAINTING FRESH WOOD OR DRY WALL PREVENTS THE PAINT FROM GETTING SUCKED INTO THE SURFACE OF YOUR WALL, LEAVING A SPLOTCHY PAINT JOB. ONCE YOUR WALL QUITS "INHALING" YOUR PAINT, ALL THAT IS NEEDED IS FOR THE SURFACE TO BE CLEAN AND GREASE-FREE.

in your case its not important to prime if yoru not going to be ther long, however i find that painting and priming are a way to disinfect. really it depends on the surface, i painted paneling,,,it didnt have to have primer but it sure made it look nicer.

if you have stains on the wall you should use a primer to make sure the stains don't bleed through the paint. in the bathroom i would use a primer like killz or similar which kills mold.