It's a hassle, it decreases range having to fly low and it limits my options. I'm not an FBO flyer going from one Signature to the next Atlantic Aviation. I mainly land at small airports where there's no one around, sleep in the plane sometimes in my sleeping bag when there's no hotels around, that kind of thing. Oxygen refilling here is impossible without going to these Signature type outfits where they'll gladly charge you $100 to park for 10 minutes or waive it if you fill your plane up with their $8/gal fuel.... And to get real long range, you have to go high. The higher the better.
There's this new oxygen concentrator for aviation that will give enough up to FL180, but it's like $10K to buy... That's a lot of oxygen tube refills.
OXYFLY - OXYFLY - Continuous oxygen supply for non-pressurised cabins