The article and comments were great information to have before deciding how to go about getting a painting job done. I think the important point is that there are several key choices (who to do the work; color, sheen, quality, of paint; how many coats; amount of prep/repairs to be done and by whom, how long the job will take, provisions for changes, how detailed the contract needs to be; advanced deposit/progress payments/final payment; final inspection, etc.) that need to be made and it requires advanced research and planning in order to become well enough informed to make the right choices. Then it requires spending sufficient time to check materials and inspect the quality of the work while it is on-going, raher than waiting to do it all at the end. President Reagan's philosophy of "Trust, but verify." applies.
To get basic measurements, measure the length and width of each wall you want to paint in inches. Multiply the length and height together, and divide by 144. This will give you the square footage for each wall. A gallon of paint typically covers around 400 square feet. In some cases, you may need a primer 2 first, then a single coat of paint, meaning that you may need one gallon of primer and one gallon of paint to cover 400 square feet. However, if the wall requires multiple coats, this will increase the total amount of square footage required, and therefore the amount of paint.
A number of factors help determine when you should paint your home’s exterior. These include your local climate and weather conditions, the age of your home, and the type of siding used. A high-quality finish in ideal conditions could last 10 years. But if your home takes a beating from the elements, you may need to repaint as often as every three years. Most homes can be on a 5-8 year interval. If you’re not sure if your house is due for a refresher, watch out for signs of deteriorating paint, such as fading and chipping.