When a garage door spring (Springs are used on a garage door to assist opening or closing) breaks the door has become very heavy because it has lost its power to open.

Replace your springs

If your door has two springs and only one has broken the other spring is still working at half strength. If your door has only one spring than it makes it very hard and sometimes nearly impossible to open.

When a spring gives way than it has come to the end of its cycles. Average springs are rated from 10000-15000 cycles. One cycle = once up and once down. As far as time, they will last from 5-10 years. If you hardly ever use your door than I have seen them last up to 30 years. If your door goes up 5-10 times a day they could last less than 5 years