If your tripmeter works, it is a very good way to keep track of fuel. Even with the working sender and idiot light on my bikes I watch the tripmeter to keep track of fuel level. I do it so I fuel up before that annoying and stress-inducing Low Fuel Light comes on.
On my bikes I can easily get 210+ miles on a full tank, but use 180 as the benchmark for refueling. Just by glancing at the tripmeter I can tell how much fuel/range I have left.