I've rebuilt/replaced every single part of a car over the past twenty-five years, and there are two things that just aren't worth doing:
exhaust and ...
front SPRINGS
That was on a 77 Cadillac. Since then I've found out it would have cost about the same as I paid for the springs alone to have the sping shop supply & install them. A few years ago I had my 73 Buick Centurion done all around for CDN$350.00 out the door.
Rear springs are a piece of cake though. I replaced mine a few months ago with moog variable rate springs, and just took them out again on Sunday afternoon to install Monroe Sensatrac coil over shocks. Regular shocks are easy with the springs in, but coil overs really need to have the spring removed as you don't have straight access to the nut/bolts at the top as with the standard shocks.