First call on site is always diagnosis - we check the springs, cables, rollers, and track alignment before touching the opener, since a bent track will chew through a brand-new spring just as fast as an old one. If it's a clean spring or cable failure, we replace it with matched hardware off the truck and test the door under full cycle before we leave.
For doors running original 1960s track or an opener that's past rebuilding, we'll lay out the repair cost against a full door or opener replacement and let you decide - given the income range around here, we'd rather spend ten minutes explaining the math than push a replacement nobody asked for. Not every old door needs to go; plenty of them just need the one worn part swapped and they're good for years more.