Choose the best quality paint you can afford; it lasts longer. Experts estimate that the outside of a house should be painted every 5-7 years, but less-expensive paint may start peeling or fading in 4 years or less while really high-quality paint will hold up a bit longer. Better Homes & Gardens[1] describes and compares the different types of exterior paint while[2] reviews specific brands. House Painting Thornton
Once you have the interior square footage calculated, experts say you’ll want to divide by 350. 350 square feet is the average coverage of a gallon of paint (though some say 250-400 square feet). The average coverage for a gallon of primer is 200 square feet. Your square footage divided by 350 square feet gets you the number of gallons of paint you’ll need. Square footage divided by 200 gets you the number of gallons of primer you’ll need. You can save money by ensuring you don’t buy too much paint. 

Having a professional paint your home from top to bottom, inside and outside has a number of advantages. For one thing, it'll save you a ton of time by not having to do the work yourself. In addition, you won't have to be concerned about safety issues, such as climbing a ladder to paint your house's gutters. Best of all, you can expect a clean, attractive finished product from a professional painter. Thornton House Painting
Exterior paint averages $25-$40 a gallon, and a 3,000-square-foot home takes 15 or more gallons of paint, or $375-$600 just for the paint. However, really premium paint can cost $50-$100 a gallon, or $750-$1,500 for that large home. Doing it yourself also requires renting a pressure washer or sprayer for $50-$100 a day; extra-long ladders or scaffolding at $20-$75 daily; and a power sprayer for $50-$100 daily, plus masking tape, drop cloths and other supplies. However, it's possible to paint a large, two-story house for materials-only costs of $400-$600. Thornton Home Painting

From clean whites and pleasing neutrals to cool blues and vibrant reds, exterior paint colors are your home's calling card to the world. Calibrate the color right and you'll have a house exterior that welcomes visitors when they roll up to your home. More importantly, the right exterior color will give you joy every time you return home, for years to come.
Lap marks are those ugly stripes caused by uneven layers of paint buildup. They occur when you roll over paint that’s already partly dry. (In warm, dry conditions, latex paint can begin to stiffen in less than a minute!) The key to avoiding lap marks  when doing DIY wall painting is to maintain a “wet edge,” so each stroke of your roller overlaps the previous stroke before the paint can begin to dry. Thornton House Painters
Once you have the approximate square footage that you’ll need to paint, remember that a gallon of paint generally covers between 250 and 400 square feet. You’ll need more if you’re painting a rough, porous material, or if you want to paint a dark house a much lighter color. Depending on your color choice, you may need a more expensive tinted primer to help with the color transition. Thornton House Painters