Is it considered OK to just prime the drywall (for example with 3 coats) and do not paint over afterwards? I suspect that a drywall primer isn't hard enough to sustain and will deteriorate, while paint will not, is it so?
The reason I'm asking is just curiosity -- after I have applied 2 coats of primer the drywall already looks neat and smooth, so I'm asking myself why do people need paint it? (My primer is white and I was planning to apply white paint)
Thanks.
In most new construction, the drywall is primed and left for the new owners to paint and they may wait for months/years to actually paint the walls. The primer will hold up under normal conditions but will not do well if you try to clean it, remove stains, etc. Most paints commonly used have a harder surface when dried so you can wipe them down with a damp cloth. This is especially true with your eggshell, gloss and semi-gloss paints. This isn't true with most primers.
I've been in the paint industry for 21 years. During this time, I have been employed at an independent paint store and served retail and commercial customers.
New, uncoated drywall should always be primed. If it's been painted before, as long as the original coat is sound and not peeling, you can proceed with regular paint.
If you looked at most primer under a microscope, it is porous to allow for the best possible adhesion of the paint. Primer is not manufactured with the same quality control as paint and it will discolor over time, and get dirty easily. Will it adhere? Sure, that's what it's designed to do. It also seals much better than regular wall paint.
I never use primer, just two coats of paint.
I always use washable paint. The new ones are excellent, able to be washed with a wet sponge many times. If the paint is not washable, when you splat a mosquito on the wall, you can either leave it there, or scrub it off, but that also takes off the paint.
So, to answer your question: check if the primer you used can be cleaned. For example you can paint a spare bit of drywall, let it dry, then stain it with your favorite food item, and try to clean it with a wet sponge.
That will give you an idea of how your walls will look like in a few years. If you like the result, then you can save money on paint and apply the last coat in a few years, when it is needed. If the paint comes off the drywall and stays on the sponge instead, then I'd strongly recommend a coat of tougher washable paint on your primer... especially if it's in a kitchen. Thanks to the primer, it'll cost less, since you only need one coat.
