Trace heart valve regurgitation

I am a 47 year overweight male. In 2004, I had my aortic valve replaced with a ST. Judes. I recently had an echo test. The test showed trace regurgitation of the Mitral Valve and to my surprise, trace regurgitation of the prosthetic aortic valve.

My question is - Should I be concerned with the Mitral Trace and with the trace regurgitation of the prosthetic aortic valve and am I at risk for a re-operation ??

My previous echo in 2006 did not indicate any trace regurgitation of the prosthetic aortic valve. Could this be due to newer technology or a deterioration of the valve ???

When a prosthetic valve fails, is it a gradual process with defined symptoms or a complete shut down, causing death ??