For do it yourselfers, dealing with the dangerous torsion springs of a rool-up garage door may not seem terribly difficult. However, getting a hold of the parts that are required for this repair job may be your hardest task.
There is definitely something to be said for self-sufficiency, but your wish to do the work by yourself may be thwarted by the commercial system in garage doors that doesn't want to take your money for the individual parts. They are usually only entrusted to installation companies.
The distributors and manufactueres of garage door opener torsion springs think that it is more advantageous for them to not retail their product directly to consumers. They can charge higher prices by restricting sales and not selling to end users, and although restraint-of-trade schemes are illegal in the United States, it's very hard to successfully overcome the situation.
In a lot of jurisdictions in the country, in fact, garage door repair is actually a licensed trade, which can lead to monopolistic situations and manipulation of the market.
Most torsion springs last about 10,000 lifts, and if you open and shut your door four times a day (twice for leaving, twice for coming home), it should last you about seven years, maximum. Each time the door opens, the tempered steel of the spring undergoes huge forces, and this can fatigue the steel, eventually leading to a horrific breakage or crack.
So you can expect to have the door repaired several times over the life of your home. It may seem economical, then, to simply to it yourself. But getting a hold on the parts necessary to do so is a huge headache.