Hi i am a garage door installer and business owner. Ive been doing this for about 6 years now. Most of the time when your garage door has a problem you can tell what it is. Like this
But other times could be more complicated to know what exatcly could be the problem. If yoyr door is to heave to lift up it probably is your garage door spring is broken. If you garage door opener wont close the door it probably is your sensor lights. If your opener makes lots of noise it could be it needs a tune up. Thouse are very easy to fix and shoukdnt cost much or anything if you could fix it your self.
Some tips on keeping your garage door working properly longer are keep everything clear about 2 fert from the rails and have a tune up about every 6 months abd your garage door should last around 8- 10 years hope this helps thanks and please follow