If they're not making noise does it really matter how old they are?
 Really?  A visual would be best but don't you think that it they were bad
or getting bad, that you'd hear it sooner or later?  Reason I ask is I have
a spare set (new) and wondering why I keep them.  Not like preemptively
replacing hoses or a fuel pump after twenty years or fuel injector hoses
after 10 years just to be safe.  I'm thinking they're either good and they
haven't gone bad (won't likely for a while) or they're bad now and you'd
know for sure.  Along the same audible hint you get when a CV is bad.

 Thoughts?

Thanks,

TJ