Primers aren't just diluted paint. They're formulated to establish a solid, even base, seal stains and ensure that the topcoats of paint go on smoothly and bond securely to the surface. "Most homeowners use latex primers, but the pros stick to alcohol and alkyd primers because they'll cover almost anything," says John Weeks, of John the Painter in Mobile, Alabama. Primer can affect the appearance of the topcoat. "It's okay to spot-prime the ceilings but not the walls, because primed spots will show," adds Span.
Most pros don't bother cleaning brushes and rollers if they are going to use them the next day on the same job. "Latex paint dries slowly in cold temperatures," says Maceyunas. For two-day jobs, he wraps the rollers and brushes in plastic grocery bags and sticks them in the refrigerator. "Just allow the roller to return to room temperature before reusing it," he says. Roller covers are almost impossible to clean thoroughly. Most pros buy new covers for each job.

Home Interior Painters