I still come across vans that have the original fuel lines in them.  Amaizing.  Some of them thirty years old.  But even if it's only twenty, it is very old.  One of the first things I inspect on a van is the fuel lines and I press how important it is to change them and to do it right.  Here in the Seattle area I do it for a good price as an emergency item, dropping what I happen to be doing.  For some I have done it and got paid later.  That's how important it is.  Who wants to see a burn spot on the freeway where a nice Vanagon burnt up.  No money is saved.  It is age related and needs to be done ASAP.  
Zoltan
425 773 4646