Much has been written about upgrades that add value to your home. Among those that we read about quite often are garage doors, counter tops/kitchen remodel, paint, etc. Although all of those are great upgrades, my experience is that a newer quality roof is the best place to start.
To begin, inspect your roof before you are ready to sell. If you do not have the means, ability or knowledge, ask a licensed roofer to conduct the inspection. If you find that the roof is in early stages decomposition, it is probably time to consider replacement. Most homes built in the 1990s and early 2000s will need a roof replaced if it has not already been done.
If a roofer inspects the roof, ask him to assess whether you may have an insurance claim. I have been involved in several transactions lately where it was determined that a claim may be justified. The homeowners then contacted their insurance company and found out that indeed there was wind and or hail damage and that an insurance claim was warranted.
If you plan to sell your home anytime soon -- and if it is an older house and the roof has not been replaced -- be prepared for a home inspection that indicates that the roof is in need of replacement. It is better to know the roof is in good shape before you put it on the market.
Although replacement will be costly, a roof that is in poor shape will raise a red flag to potential buyers. I know of no other issue that jeopardizes a sale more quickly than when the buyer finds the roof is in final stages of decomposition. A roof in its final years of life will likely cause a buyer to cancel an offer to purchase or ask that you reduce the price of your home to compensate for the cost of replacement.