Amazingly, my RV has the original olives still I'm sure with no leaks *bloodies knuckles from wood knocking*
My truck's IP supply line gets a bit leaky now and then, but I found that I can loosen the nut and retighten it. Last two times I did it, it lasted a year before I had to do it again. It's possible they could have been replaced at some point though since some fuel system stuff has been messed with.
I bought new olives for the truck but never installed them. I have them stashed in the RV now.