Back when I worked at K-Mart (late seventies, early eighties) one of the departments I worked in was Building Materials. Sold a lot of drywall, paneling, and concrete. And when storm doors were on sale (white crossbuck) we must have sold 30 or 40 a day. Back them they were pretty simple as they were prehung. All you had to too was set the door on the brickmold, square it up and screw it in. Usually took an hour or so.
My new door was like putting together a kids toy on Christmas eve. It's a full length glass door (no picture as a storm blew up just after I got done) that needs to the hinge attached and the frame built. It took ~4 hours to get it right but it looks pretty good. Buffy the Cockatiel Slayer (our Cocker Spaniel) won't go anywhere near it even though she can look right out.
It's real strange - I keep seeing the door out of the corner of my eye and I think its open as there is so much glass. Glass to keep clean... Well - thats the wife's job. :-)
Update: The weather cooperated (it's hot enough for the A/C).