Some paints are two-in-one paint and primer products, or so-called "self-priming paints." These paints are designed to seal and cover surfaces in one coat. But, here's the secret: though it's called a paint-and-primer-in-one product, there's actually no primer in the mix—what you're really working with is just a thicker paint that often doesn't perform as well as using separate primer and paint.
If you have kids, pets, or occupants who will damage the walls, it is recommended to go with washable matte, eggshell, or satin, because these paints can be easily cleaned and are more durable. However, flat paint can be touched up more easily and hides imperfections better, so if you are selling the home, it is highly recommended to go with flat. Bathrooms with showers/tubs should go in semigloss- unless you are selling or want a specific design look, then use satin.
Prep work should include removing all loose paint, either with a pressure washer or by scraping; removing any trace of mildew using bleach and water or a commercial solution, and sealing or covering dark stains; caulking all seams, corners and around windows or trim; applying epoxy filler to repair serious woodwork problems; covering dark stains; sanding all rough surfaces, and priming the bare wood with a bonding primer.
Many new homeowners want to change the color scheme of their rooms, either as a way to personalize the space or match the walls with existing furnishings and artwork. Interior house paint is relatively inexpensive, and it doesn’t require complicated machinery or professional-level skills to apply. There are also thousands of customizable colors available, as well as a choice of finishes, such as matte, semigloss, or gloss.
Supplies and Equipment – Scraping, sanding, and stripping tools and supplies; patching compound; power washer rental; primer; caulk; masking supplies; painters’ tape; ladders and scaffolding; paint pans; brushes, sprayers, and roller brushes all cost money, even if you do it yourself. Consider all of those tools and equipment sitting in your garage for the rest of your life vs. paying an experienced painter to do it all for you at a price that saves you weeks of time. Expect to pay $5–$6 per 100 sq. ft. for supplies and materials.