A torsion spring under tension is not a weekend project, full stop - that's true whether the door is five years old or twenty. Where DIY makes sense in Keller: tightening loose hinge bolts, cleaning and lubricating tracks, replacing weatherstripping along the bottom of the door, or squaring up a photo-eye sensor that's gotten bumped out of alignment. Where it doesn't: anything involving the spring, the cable, or the drum, and anything where the door is binding on the track hard enough that it's fighting the opener. On a 1999-era double door, the spring is sized to lift real weight, and a spring that lets go while someone's adjusting it can break fingers or worse. If your opener runs but the door won't lift, or lifts only partway and reverses, that's almost always a spring or cable problem, not an opener problem - worth a call before you start troubleshooting the motor.