Bog box stores carry a lot, but what it lacks (not just an employee when you need help) is knowledgeable people on products. These stores carry a lot of brands, and the brands given a little pamphlet on the product, but there are so many variables when it comes to doors, limits, and even limited style choices.
I mention this because as a small business it's important to weight your options. 1) What's important to you? 2) What is your budget? 3) Can you benefit your local community by supporting local?
Here is a couple images of Door replacements that I've personally done. I hope you love them!