running out once, or nearly so, is the only way to find out how far you can really go
I take my average figured out by filling, resetting trip B. Riding, refilling and see how many miles I have gone and how many gallons I have used
for example filled, trip B zeroed, rode 150 miles, refilled (and trip B re-zeroed), took 3 gals even to refill = 50 mpg.
Times fuel tank capacity of 3.9 gals for a std x 50 mpg = possible range of 195 miles before pushing
I have gone 225 miles on my dlx with 4.7 gal tank and still had .5 gal left in tank (took 4.2 to refill) so I figure in an emergency I could go 245-250 miles before pushing.
I don't "push" it though and usually fill up between 150 and 200 miles on a tank