Do the cleanup. When the painting is done, send the painter home and do the cleanup work yourself. This will include rolling up drop cloths and collecting scrapings, removing painter's tape (use a hair dryer on low heat to soften the adhesive), cleaning paint brushes, rollers, and other tools, replacing electric switch plates, outlet covers, and light fixtures, and sealing any leftover paint cans and storing them in a dry, temperature-controlled location.
While many professionals use paint sprayers, they can leave drips and uneven coatings in the hands of an inexperienced user. If you’re set on DIY house painting but don’t have much practice, you may want to stick to rollers and brushes. Brushes are great for edges and smaller areas, while rollers can be used to paint large and long surfaces like siding and trim.
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Use semi gloss for hallways because walls there are more likely to be touched, bumped or otherwise marked over time (semi gloss cleans more easily). However, use flat for a living room. Flat will help hide imperfections in the walls. If you want the same color in both the hall and living room, then no problem. Use flat in the living room, semi gloss in the hall, making the threshold the transition point.
Prime. Dark colors, stains (once sealed), and previously unpainted surfaces (drywall, spackle, etc.) will need a primer coat, usually white. NOTE: most paint stores & home improvement centers will now tint primer (at no charge) to match fairly close to the color of the finished coat, that way two coats of primer need not be applied.[6] Although not all surfaces need a prime coat, skip this step at your peril! Dark colors will likely show through the first -- or even the first couple-- topcoats of paint. Sealants and unpainted surfaces like spackle patches will absorb or repel moisture in a topcoat at a different level than the areas surrounding them. Applying a good primer coat will help even out these differences. Primer equalizes a wall to a uniform surface. It's like erasing a canvas before drawing a new picture. Although some will argue the point, you generally don't need to spend a great deal on primer or buy special primer. A cheap, 5 gallon (18.9 L) bucket of plain, flat white paint will usually do the trick and cover a large area. Give your primer at least 24 hours to dry (follow its instructions) before applying a topcoat.
Containing either natural oils or a synthetic alkylate, oil-based paints are more durable than latex paints. Oil-based paints should be used on surfaces where you want the finish to last for a long time. While this kind of paint has a stronger odor and takes longer to dry, its durability is unmatchable. The strength of oil-based paints makes them a great choice for moldings and trims.
Plan the schedule. Get a grip on the time it will take to bring the project to fruition. Plan for time to move furniture, wall prep, cut in, the painting itself, eating and breaks, and don't forget cleanup and bringing furniture back in. As you plan, err on the side of prudence. Unforeseen events will slow you down, so allow time for these. Remember, this is a multi-day project. Don't try to fit too much into a day. If you move faster than planned, great!

Following the same process as the primer, cut in the walls with your chosen paint. For best results, paint one wall at a time. This makes it easier to spread the paint while it’s still wet. Work from top to bottom, rolling the paint in V or W-shaped strokes. Before applying a second coat, wait two to four hours. Then proceed with the same process used for the first coat.

A single gallon of paint can run anywhere from $20 to $80 per gallon. Professionals get a contractor discount of anywhere from 25 to 50 percent. For rough siding, like stucco, you’ll need to use 10% to 20% more paint. Some textures, like wood and stucco, require extra paint because they have more surface to cover in a tiny area compared to smooth siding. Use the highest quality exterior paint your budget will allow for your project. It will look the nicest and save you money by offering better coverage and durability. Better coverage means fewer coats and fewer work hours. You’ll also go a few years longer without needing to shell out more cash for a new coat. How do you know how much paint you're paying for? Here's some helpful math: