1. Most people have not maintaining their garage door on
the list of things to do home projects. Adding it could
save you from having to buy a new overhead door
sooner rather than later though.
2. To maximize the lifetime of the garage door to keep what
you have. There is much to do and won't take long. Check
the system trying to open the door without door opener.
3. If there is any tension or fix, the problem is probably the
electric motor. You can try to fix it by following the
owner's manual, but it can be difficult if you are familiar
with repair garage door opener.