A full door swap is not a weekend DIY project, and the part that gets people hurt is the torsion spring - it's under enough tension to break a bone or worse if you don't know the winding bars and the drum setup cold. On a 1994-era door, that spring has had thirty years of cycles and may let go unpredictably even when you think you've got it under control.
What you can reasonably do yourself: swap weatherstripping, lubricate rollers and hinges, tighten loose hardware, and watch for the early signs - one side dropping faster than the other, a grinding sound on the track, a door that reverses on the sensor for no reason. Catching those early doesn't save you the install, but it buys you time to plan it instead of doing it as an emergency.