I'll have to disagree to some extent there Greg. It depends what you are buying. While TR's comment might have been exaggerated, there is a pretty substantial difference in the quality of most of the window and door products that you will find at a big box store compared to those sold and installed by professionals... The progression for me was: first, I installed doors that clients would purchase at box stores despite that I did not recommend it. Then, after realizing that they typically took twice as long to get set right do to poor assembly/manufacturing tolerances, i had to start charging more for those doors. Then, after ALWAYS having them be a PITA, and dealing with service calls a few years later, i decided that i could no longer install or recommend them at all. Sure there are some exceptions like Andersen wood windows, Simonton windows, and Thermatru doors from lowes, but the majority of the stuff that you find on the shelf is not good quality. I'd love to be able to sell a door that only costs $150-$300 instead of $500-$1000, especially when they really look about the same to the untrained eye. Unfortunately, when even a perfect install of that product results in issues down the road, that starts to affect one's reputation. That is the reason why most professional window and door installers won't touch them with a 10' pole.