How much fuel do you keep in your tank?

[javacontour]

Depends on the car. I usually don't fill the 99 MGM as it sits most of the week. I just drive it on the weekend to keep it moving. I try to not let it get below 1/4 of a tank, but don't want to fill it so I have gas go stale. So I'll put $10 in it every so often. Other times, I'll fill the trunk with my empty gas cans and drive over to MO where gas is cheaper (currently $0.50/gal cheaper) if I have other errands over there and fill the car and the cans before I come home.

The 12 Mazda3, I try to fill it when I have about 100 miles range remaining indicated, or right around 1/4 tank. But I drive it just short of 2k miles/month, so it gets filled 3-4 times each month.

 

[Shaman]

After 3/11/11 in Japan, I fill at half tank. Leaving your car parked at a gas station the night before just to get 2 gallons is not fun.

 

[javacontour]

We are prepared for "snow doom" in St Louis, so the cars are filled. (Well, don't know about the 26 year old boy's 2010 Altima, but the Mazda3, the RAV4 and the MGM have more than 3/4s of tank each.) we have two jugs of milk and enough bread and eggs to make french toast for a small army.