After years working on homes, I can tell you exactly why garage door springs give out early. It's either a bad installation or ignoring how heavy the door is. A heavy door will chew through the wrong spring in no time. Before you buy parts, check the door's specs. Also, have a pro look at it once a year. It saves a lot of hassle down the road.
I've seen new springs go bad in just a few months because a door was slightly off balance or never got lubricated. Once we started tracking maintenance schedules for each project, those emergency repair calls almost stopped. My advice is to write down every service you do and set calendar reminders. You'll get years more life out of the springs and avoid those thousand-dollar emergency bills.