I see more of the 'wound' springs than extension springs. A lesson I learned from Mark Cramer is to check the garage door for balance. If the springs are adjusted correctly, then the door should not fight too hard to move from any position along its track. I disengage the auto opener, move the door to about its halfway point, and check whether the door fights hard to move up or down. If it does, then the auto opener (or person) is working harder than it needs to. It's amazing how many people ask, "How did you disconnect it from the auto opener?" so I get to show them that as well.