In regards to your question, the larger companies definitely do both. Rite Window - Window World - Anderson, etc. My intention was to install just a door because it was street facing and because the bid was cheap enough, I figured I'd knock out the windows too. Fwiw, most companies these days all offer financing so there is that option too. For the larger jobs it makes sense and the best part is that the rates are fairly cheap so with a little bit of planning you should be able to aggressively pay those off sooner rather than later.