My wife is one of the ones who has to get gas NOW if she's below a half tank. I don't think I've ever seen hers on 1/4 tank.
On the fuel turnover thing-maybe about 5 years ago I had a tank phase separate in my MG. That was an absolute mess. Even after I'd pumped the tank out, flushed IPA through the system, and everything else I was still fighting it. After I'd done the clean up, I still had no power and found the carburetors full of silt(that's the best way I could describe it). Cleaning that out didn't accomplish much, and finally I backflushed the jet assemblies and got something back to normal. Still, though, I was left with the jets halfway into the "enriched" position, and once I got them back to normal they wouldn't move at all so I had no choke. I finally swapped them out for another set and mothballed those, then finally had them rebuilt along with the engine rebuild. The guy who did them told me they were an absolute mess.
Even at that, I was running two filters for a while and for a while was changing them out nearly every tank. I remember NAPA making me a deal on a dozen of the little thimble filters. I'd get an occasional rust "booger" in the short line between the gas tank and the pump that would make you think it was out of gas, and I'd end up undoing the line at the fuel pump end and just letting it drain a bit. I did that on the side of the road once and in the parking lot at work once. I finally changed the tank with the engine rebuild-a new 16 gallon tank(original was 12 gallons) which is kind of nice but I also sort of regret it since I don't turn it over as often and this is a totally open fuel system without any evaporation control.
On the "the battery is bad" think-once again I've had more than a few roadside adventures in the MG and have been asked that plenty of times. The last time I had a roadside stop, it was my not getting the distributor "snugged down" enough and it popped out of engagement under acceleration. Someone stopped and helped me push it off to the side of the road, and he stood there as I popped the hood, surveyed and saw the problem, then reseated the distributor(I was a few blocks from home so could have walked if need be...). He kept asking about a jump, and as soon as I put the distributor cap back on I said "It's going to start." He says "You think so?" just as I hit the starter relay from under the hood and it starts right up.
I have to admit that even though modern cars are so much more reliable, I appreciate how simple old ones are...