Test different paint swatches. The last thing you want to do is paint a whole room and then decide you despise the color (yes, it happens!). Try out different paint colors on the surface before choosing the paint that you want. Buying sample sizes will help you save money. The caveat: paint color samples are not real paint, so if you try to finish or touch up a project with samples, the paint will fade.
At least 90% of painting time goes into setup, prep work, and priming. The method of prepping required varies for each type of exterior material on the home, but every project must be patched and cleaned. The more thoroughly you prep and prime your home’s exterior, the longer your paint job will last. You could save quite a bit if you do this part yourself, but it must be done correctly, or your contractor will have to go over what you missed. The prices mentioned are based on paying a contractor to do each job rather than one overall quote for the work from start to finish.
An example of the wall measurement would be: 40 linear feet of bedroom space, x 8 wall height, =  320, x 2 = 640. Minus 1 door (60) and 2 windows (80) = 500 sq feet being painted. Then divide the 500 by 400 (sq feet per gallon), and you get 1.25 gallons (4.73 L) needed for that room. For this, you'd need 1 gallon (3.8 L) and 1 US-quart (950 ml). If the amount it comes out to is over 1.3, we recommend just getting 2 gallons (7.6 L) so that you have leftovers if needed, since 2 US quarts (2,000 ml) costs essentially the same as a gallon in most stores.
Use a roller to paint the rest of the wall. A good method to use is the 'W method'. You start by painting a large 3 foot (0.91 m) square W on the wall. Then, without lifting the roller, you fill in the W.[7] You can paint a wall section-by-section, and do the walls one at a time for best results. It's generally a good idea to use an extension pole for your roller instead of standing on a ladder. Make sure that neither the extension pole nor the roller has plastic handles, as plastic handles are flexible and this makes it difficult to control the painting.

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: