There are people who will insist that running your tank down until the fuel light comes on is harmful. I say, nonsense! If that is true then it's a damned poor design. Early fuel pump failures are more correlated with manufacturer than fueling habits.
Purely anecdotal, but consistent over several different makes and models I've owned, in my experience I almost always run a tank down until the fuel light comes on or the needle is just hitting the empty mark before filling up. I have never had a fuel pump failure, and I routinely keep cars well over 100,000 miles.
Of course, it does no harm to fuel up sooner, but the manufacturers put those fuel warning lights in there knowing the parameters of how much fuel is left in the tank and how the fuel pump works. They'd be foolish to intentionally set owners up for fuel pump failures. That kind of bad reputation is hard to overcome.