Head Gasket!

Recently I had my car service and told them I had a slight oil leak for the past year. They recommended replacing my head gasket to correct the problem.My 2002 subaru only has 58,200 miles. What is the risk if I continue to drive my car & check the ooil frequently, so far I notice my oil is always on full.

As long as you maintain the correct oil level there is no risk at all. Where is the oil leaking from?

This sounds like a valve cover gasket issue, not a head gasket, but in any case if you keep it full mcparadise is correct - no risk.