The lifespan of a modern roof is measured in decades rather than years. Some roofs will need replacement after about 20 years, while others can last half a century before needing replacement. Professional installation is one key to a long-lasting roof that won't need replacement anytime soon. Regular inspections and maintenance will also increase the life of your roof, reducing the need to replace it. However, when your roof reaches the end of its natural life, you should replace it before the rest of your home suffers.
You should also re-roof your home whenever part or all of the roof experiences damage from a catastrophic event. Home fires, floods, heavy snow and ice, storm winds and lightning strikes can all damage roofs severely. Without re-roofing, your home will be at risk of water damage from rain and snow. You'll also lose a great deal of your thermal efficiency as warm air escapes through the damaged portion of the roof. Regardless of how often they occur, disasters that harm your roof should be cause for re-roofing.
You should consider re-roofing your home whenever you begin to make plans to sell. If the roof is old or cosmetically damaged, buyers may be unwilling to meet your asking price for the house, because they know they'll soon be liable for thousands of dollars in roofing costs. Investing in a new roof will not only allow you to stand firm on your asking price, but it will also attract more buyers and may help you sell your home more quickly.
The schedule for re-roofing your home should also depend on when you can afford it. Low interest rates on second mortgages and home improvement loans will make a new roof more affordable in the long run. Even if you don't plan to sell right away, or if your roof might last an additional year, it may be in your best interest to pay for a new roof now to avoid the chance of not being able to afford one when you need it.