Installing a new roof yourself is not recommended. But if you're considering whether or not you can do it, it's absolutely possible. Tearing off the old roof is just muscle and sweat. The truth is that anyone can replace their own roof with the help of the many DIY websites.
Ultimately, my answer is yes, you can repair or replace your own roof, but I rarely suggest that you try it. There are too many ways to cause damage to the roof or to yourself if you don't take the proper precautions, and ultimately these can end up costing you much more than the money you saved by NOT hiring a qualified contractor in the first place. All that said, choose a contractor carefully and do some research, don't hire the first one to stop in a van with a hammer. Make sure that you are licensed and insured and that you have the right qualifications to do the job well.
DO NOT think that you will save money by hiring the cheapest type, most of the time they will cost you much more in the long run. Check with the BBB to verify the contractor's credentials and how long the contractor has been in business. Skipping a self-made roofing step can be catastrophic for a homeowner. While some lessons are learned the hard way, reroofing a house doesn't have to be one of them.
If you have more technical experience, replacing a roof on your own will save you thousands of dollars in labor costs, but be realistic about your skills and strength. The best way to distinguish between replacing or repairing a roof is based on the severity of the roof damage. If you have T-lock shingles, you'll need to replace the entire roof, as they're discontinued, but your insurance will normally cover the costs. If you're a novice DIYer, doing small repair jobs, such as replacing shingles, is a smart way to learn more about how your roof works and save money.
For residential homes, roof replacements usually take two days: the first day to remove the old roof and the second day to install the new one. Professionals can replace roofs in a matter of days, but doing it yourself requires an indefinite amount of time. Here's when you should and when you shouldn't, and what you should know about roof replacements and repairs to help you decide.