Damp is very damaging to Oriental carpets as they are always made from natural materials - wool, cotton and/or silk, which are susceptible to rot through dampness. Wool in particular is susceptible to shrinkage so should not be left wet for extended periods.
Intense heat, i.e. in front of an open fire, or dried after cleaning with heat dryers is generally bad for rugs as it dries out the natural oils in the wool making it weak and brittle.
Excessive direct sunlight can cause fading over a number of years. Whilst some fading is often desirable and natural, too much ruins the look of the rug and reducing its lifespan by damaging the pile. This can be prevented by blocking the direct sunlight using blinds or curtains when the room isn’t in use. Pay attention to the placement of your rug, rotating it from time to time to gain a subtle and even fade in colors. A rug which is faded all over can have a soft, muted appearance; one which is much lighter at the top than the bottom does not look as good.
Keeping to these practices should help you to maintain the look and condition of your rug.