Having blown off shingles does not necessarily mean your roof is due for a complete re-roof but it is definitely an emergency problem that needs to be addressed immediately. Bare spots are not protected at all from the elements and a simple spring shower can cause major leaks. Have your roof inspected at the same time as the repair.

This usually occurs where you have the most sun exposure. If you see this on your roof it usually means the shingles tar line seal has been broken which leaves your roof vulnerable. Have a professional come look at it before winter so you don't have a spring surprise.

This is also a very good sign that the roof's lifespan is almost over. Discolouration is another way you can tell this is happening.

Open your attic hatch and have a look, if you see buckling of the plywood, dampness of your insulation or even light coming through, there's a very good chance that you've already had some water infiltration. Don't wait until water has come through the drywall to do something about it, prolonged leaking will cause more unexpected and preventable damage to your home and wallet!

These areas are the most concerning as they are the areas that collect the water and absorb heat which makes them more susceptible to water infiltration; if you see curling or deterioration in these areas please have a professional come look at it.