Tank capacity is there to be used.
With any car you drive regularly, you have the trip odo and the fuel gauge as guides, since you already know what the tank capacity is along with fuel economy for the conditions you're driving under.
In areas you regularly drive through, you already know where the cheapest gas stations are located.
In unfamiliar territory, I might fill up early, but in areas I know well, including some long highway runs, I have no qualms with running a tank down to a very low level, to include the low fuel light. The only thing we currently have that lacks a low fuel light is the E350. For the rest, you have at least another fifty miles of fuel remaining when the light illuminates, which is no risk at all in areas you know well.
I might not like seeing that light in West Texas, the Dakotas or Montana, though, so in areas where gas stations might be widely separated, I'll be looking for gas at around a quarter tank.
The Gasbuddy app is handy for finding the cheapest fuel wherever you might be.