I have a '01 Firebird that I waxed with NXT almost every week last summer and was very pleased with the results. The car was stored for the winter. With a little nicer weather I was able to start driving it again. It still looks as good as it did when put away for the winter.Anytime it gets worse than dusty,I wash and wax.My question is, do I have to strip the wax that was applied last year or can I continue my routine?