How long on wait to start

Just a question for all the diesel owners out there. How long does your wait to start light stay on. I know it depends on temp and all so lets say 50 degrees temp with a humitity of maybe 70% or so. I've never had any starting problems with my 00 250 but just wondering what kind of life to expect out of the glowers. It only has like 122K on the dial and I live in MS so the temp is rather warm all year. I always allow the wait to start light to go off even if it has ran for two days straight. I'm just courious to what is normal.

The glow plugs on the '95 up 7.3L "PowerStroke" engines will typically last a lifetime. Yes, a lifetime.

The relay however, may have a life of 6 months to 10 years depending on many variables. Basically, check the RELAY first!