I've owned my 2005 Duramax since new, it now has 243,000 miles on it. I've never had the WIF indication either. I had a 2007 Duramax I put 36,000 miles on, never had WIF on that one. At work we had an '02 Duramax with the wires broken off the sensor. In several years of ownership we never had any fuel related problems other than needing new injectors like all the early LB7 duramax engines needed.
I don't think it's a big deal but, it can't be that expensive of a part to replace. I tend to keep my vehicles repaired no matter the problem. Have you priced a new float? They're only about $50.
