G'day Harry,
Sorry to say, I'm not going to be very helpful but anyway,,,not much response to date, so here goes.
Generally speaking, Nissan service will give you a long list of needed repairs which together with parts and time may, just may, cost a bit. Even a fair bit. Even quite a large fair bit.
Is the hose, at any point leaking?
Can you tighten the clip/ring/whatever up a bit more? My 08 model shows no leaks at all.
The clamps should not be 'worn out' really, they generally last the life of the donk so if there is a leak, it's most likely to be the hose, not the clamp.
My understanding is that silicone pipes/tubes/whatever will last either forever or at least much longer than the old fashioned rubber. BUT I must admit, I've not had this problem and therefore cannot give you a definitive answer.
Get a bright torch and look for leaks, spend about a half a life time searching the web for your problem and suitable materials and hope that someone who has a clue gets an answer for you.
Luck,
C ol