The first and most integral step to proper roof maintenance is regular inspection. Every few months, you should make sure to check your roof for any rust (if you have a metal roof) or for holes, tears, blisters, or loose seams if your roof is made from asphalt roll.
In the case of a leak, it is recommended that you apply roof tar to the suspected area of said leak after scraping the area clean of gravel.
If you find a blister on your roof, chances are it is caused by moisture. If that’s the case, you’ll want to cut down the middle of the blister with a knife. After it dries up, fill up the area with roofing cement; preferably with a caulking gun. Once that’s done, put roofing nails on each side of the split, and then cover the split and the nails in more roofing cement. After that, cut a patch of the same or similar roofing material larger than the damaged area; nail it on top of the blister. Finally, seal the edges with more roofing cement.
If you have an aluminum roof and it’s leaking, you can fix it with fiberglass mesh. Cut two pieces large enough to cover the area you want to fix, then clean the area with a wire brush and use a putty knife to apply roofing cement to the area. Once that’s done, put more fiberglass mesh over the cemented area, and then apply more cement over that. Cover that layer of cement with yet another piece of fiberglass mesh, and finish it off with one final layer of cement.
If you have an asphalt roll roof, you may want to consider painting it with reflective asphalt aluminum paint in order to protect it from the sun (which is all that much more important if you live in a warm climate). Doing so can reduce temperatures on the roof by up to 100 degrees Fahrenheit (which can also reduce cooling bills). Additionally, the paint will re-seal the surface of the roof, protecting it from water damage.
Unfortunately, no matter what measures you take, you will eventually have to repair your roof, in which case you may want to use asphalt roof coating.
In addition to the above, you will also want to look out for things such as snow during the wintertime, stray leaves and branches (as well as connected branches that hang over your roof) and other debris, moss, algae, and various fungi, and birds/bird nests/bird droppings.
You might also want to look at the underside of the roof from your attic. By doing so, you can see if there are any dark patches, streaks, rotting wood, mold, or dripping water, all of which are signs of an impending leakage If you see any of these signs, take care of it immediately before any serious damage is done.
As mentioned above, all of these checks should be done regularly, and any problems should be taken care of swiftly, as waiting too long can cost you valuable time and money.