I am going to do valve adjustment in the near future. The factory manual says to reuse the valve cover gaskets and use some sealer. The bike does not leak at all and I want to keep it that way. but I am figuring that these rubber gaskets are almost 10 years old. Should I just replace them due to age or inspect hem and reuse? Also I looks like there are a few O ring type gaskets that the manual says to replace. Anything else I should be replacing during a valve adjustment.