If your garage door is somewhat old and worn down and in danger of breaking, you may want to take steps to protect it and your family from possible harm.
Step one: replace the old lifting springs. They're pretty clearly the most important and the most potentially dangerous part of your garage. They can wear out and break, causing injury, sudden dropping of the garage doors, and more. Have your springs professionally inspected, and if they need it, replace them. If they're just squeaky, spray on some lubricant.
Step Two: Check the Integrity of Your Safety Cables. Have a careful inspection at the tense cables that attach the spring to the brackets on the bottom of your door. If the cables are in any way worn out or damaged, they're in danger, and they should be replaced, again by a professional.
Step Three: if your door doesn't open and shut as smoothly as it did when you first bought it, you should check and find out what is causing the delay, because the source of the disturbance may later become a source of breakage or danger.
Step Four: Put in Some Teamper-Resisten Brackets. Every garage door has bottom brackets that are connected to the springs. The brackets are always under a lot of pressure from the forces exerted on them by the tense springs, and may require replacement. Lots of different manufacturers produce products that resist being tampered with.