I have a 2001 Nissan Xterra. I'm told that I need to replace the engine, radiator, waterpump & timing belt.
My car was still in running condition when I towed it to the dealer. I'm getting different advice on if it needs replacement vs. repair from acquaintances.
I want to know if anyone can clarify how long a car can be driven with a condition that will cause the blown head gaskets.

You may first want to insure that it is a head gasket problem. Maybe it's a intake gasket problem.