Lubricating hinges and rollers, tightening loose bolts on the track brackets, and testing the auto-reverse safety feature are all things an owner can do without a ladder emergency. What we'd stop you from doing yourself is anything involving the torsion spring itself - those are wound under enough tension to break a wrist, and on a 1993-era door the spring has usually seen three decades of temperature swings that can make the winding cone brittle. If your door is still original to the house, treat the spring and the cable as professional-only parts, full stop. Everything else on a maintenance visit - lubrication, balance check, sensor alignment - is low risk and worth doing between our visits, not instead of them.