This is a question I am often asked,
The easiest answer if you want to be reactive is replace the spring when the spring breaks if there is more than one replace all of them at the same time as they are on the same cycle life, if you are a proactive person then replace the spring when it is close to the end of its cycle life.
The spring "Cycle life" Whether an Extension (the type that stretch), or a Torsion (the type that twist), is based on “cycles” how many times the spring is stretched and contracted, or wound and unwound.
The springs are manufactured several ways, what is important is how they are rated for Life Expectancy.
After calling several local and National Companies most responded on average that there standard spring change and spring used on new doors are a 10,000 Ten Thousand to 15,000 Fifteen thousand Cycle Spring/s.
So do the math based on the average.
The national average number of times a garage door cycles in one day is four times.
4 cycles per day multiplied by 365 days equals 1,460 annual average divided into 10,000/15,000 cycles equals 6.84/10.26 years, lets round for ease of the math and say 7-10 Seven to Ten years respectively.
So the next question how do I determine my springs cycle life?
I am obliged to address that there are defiantly higher cycle springs made for the garage doors and are often depending on the company you choose much more expensive, the question you need to ask yourself is how long do you plan to live in your current home before you purchase a higher cycle spring and get several estimates before purchasing you can have springs made for any number of years of cycle life I have installed spring designed to last up to Sixty years.
That being said understand that unless there is visible spring damage showing there is no way to determine when the spring is going to break by looking at it, Logical math will get you close but without knowing how many times the door was opened and closed during the springs lifetime an accurate estimation is about as close as anyone can get.
So to simplify:
1. Count how many years it has been since the last spring change and base it on the national average.
2. Have a professional measure the spring to determine the cycle life the spring was manufactured to withstand and bounce that off of how old the current spring is.
3. Beware of the salesman and do your homework on the companies you choose to avoid unnecessary expenses. Check throe reviews and track record and of course check Angie’s list for the best references.