Is there a life-expectancy of an outside aerial?

An aerial over 8 years old can corrode and become less sensitive at certain frequencies, or water can leak into the cable.  If you are in a very exposed area or on the coast, it is more likely your aerial gets damaged or worn out quicker. A health check of the installation by a qualified aerial installer could reveal the issues and what changes could be made to improve the signal.

Further information on aerial installations.