Technically it is when the gas light comes on, which is probably closer to 1/8. But I rarely am further than a couple of miles from a gas station, and my daily commute is shorter than the amount of gas left if I can't fill right away, as I can do it the next trip. Your "at what level" question is vague--I go seek a gas station at empty, and fill to full. Who refills their tank at full?
When on road trips I keep a closer eye on it. I have never run out of gas enough to stall.
And because my driving is very predictable, I tend to go empty about once every two weeks, and so I get a car wash at the same time at one of those drive-through washes, which is only $3 with gas. When I have to fill at a different gas station, my dusty car bugs me.
I'm a slacker - I almost never fill it up unless it's on empty :) The one exception is if I'm coming across the border from the US to Canada, where I almost always fill up on the US side because gas is so much cheaper there.
I almost always wait for the fuel indicator as well, and I count that as "empty", even if it's technically more like 1/8 tank. :-} (Mine actually seems to come on around 1 gallon remaining, out of an apparent capacity of 11 gallons.)
I drive zipcars; the rule is that they must be returned with at least 1/4 tank, so I refuel then. When I drove my own car, I would refuel at the last possible moment.
There's a point - it's about halfway between 1/8 and Empty - where if I have to park my car facing downward on a hill, the gas is wrongly positioned to flow into the intake (or something - I've never seen the inside of my gas tank, so I'm really guessing). Therefore, I have to refill when it gets to that point, or I risk embarrassing calls to AAA.
I tend to fill mine around 1/4 tank, but if I know I'm going to be going someplace and have around or less than half tank, and think I may need to gas up enroute, then I will fill it before I start my trip. So it really depends on the circumstances for me.
I don't really understand the difference between gas tanks and lithium-polymer batteries, so I let my gas tank run down almost all the way to empty before recharging it.
During the cold season, Anton told me to fill it up whenever it gets to about half a tank because he said you don't want your gas tank too empty when it's cold out. Since I grew up in lands of year round warmth, I take his word for it, although it varies depending on how cold and windy it is outside when I get close to half a tank. During the warmer months I tend to fill it up at around 1/4 tank, because I'm paranoid.
Because my abode is about 1/6th of a tank away from the nearest metropolitan area, if I'm at 1/4 and I expect to go metropolitan twice, I'll fill or top up. Fuel prices in NZ are rocketing at the moment.
Quite a lot of my driving is in the 100-mile round trip range (that's the round trip to my mom's house, for instance), and I don't care to set off for that with less than a quarter tank, so it seems like that's usually about where I end up filling it. If I'm just tooling around locally, though, I'll let it get to the point where the indicator comes on (just below 1/8), and then go fill it up as the last thing before I go home on that particular trip out; I've discovered through practical experience that if I decide I'll wait till the next time I head out, I will be running late that time. :)
Usually it's somewhere below 1/4 but can be higher if it's Friday. This is due to passing three gas stations on the way to/from work but it requiring a special trip otherwise. Thus my fill level is most strongly correlated with my own laziness/convenience.
Yeah, I figured "My refueling decisions are not well correlated with the level of fuel currently in the tank" might be the answer for some people as well as me. :)
(no subject)
Date: 2011-03-07 08:07 pm (UTC)(no subject)
Date: 2011-03-07 08:08 pm (UTC)(no subject)
Date: 2011-03-07 08:09 pm (UTC)(no subject)
Date: 2011-03-07 08:09 pm (UTC)When on road trips I keep a closer eye on it. I have never run out of gas enough to stall.
And because my driving is very predictable, I tend to go empty about once every two weeks, and so I get a car wash at the same time at one of those drive-through washes, which is only $3 with gas. When I have to fill at a different gas station, my dusty car bugs me.
(no subject)
Date: 2011-03-07 08:11 pm (UTC)(no subject)
Date: 2011-03-07 08:12 pm (UTC)(no subject)
Date: 2011-03-07 08:16 pm (UTC)(no subject)
Date: 2011-03-07 08:21 pm (UTC)(no subject)
Date: 2011-03-07 08:28 pm (UTC)When I had my own car, I would refill it at around a quarter tank.
(no subject)
Date: 2011-03-07 08:29 pm (UTC)3) What fraction does "soon after the indicator light comes on" correspond to?
(no subject)
Date: 2011-03-07 08:31 pm (UTC)(no subject)
Date: 2011-03-07 08:34 pm (UTC)(no subject)
Date: 2011-03-07 08:38 pm (UTC)So it really depends on the circumstances for me.
(no subject)
Date: 2011-03-07 08:43 pm (UTC)(no subject)
Date: 2011-03-07 08:53 pm (UTC)(no subject)
Date: 2011-03-07 08:53 pm (UTC)(no subject)
Date: 2011-03-07 08:55 pm (UTC)I rarely wait for the light to come on
Date: 2011-03-07 09:15 pm (UTC)(no subject)
Date: 2011-03-07 09:28 pm (UTC)"tank" implies there's liquid fuel, not batteries, but I will certainly change the question to clarify.
(no subject)
Date: 2011-03-07 09:29 pm (UTC)How would you clarify the question? I mean to ask what level the respondent decides to refill the tank.
(no subject)
Date: 2011-03-07 09:31 pm (UTC)I believe this is vehicle-dependent, so I thought I would leave that to the respondent to answer.
(no subject)
Date: 2011-03-07 09:32 pm (UTC)But what did you do when you did fill the tank in a vehicle? I mean, if you ever did fill the tank on a regular basis.
(no subject)
Date: 2011-03-07 09:33 pm (UTC)I am wondering, though, what you did when you did fill the tank in a car, assuming you ever did so.
I suppose I should think of a way to clarify that.
(no subject)
Date: 2011-03-07 09:39 pm (UTC)Do you drive an all-electric car? Or, instead, do you drive a hybrid?)
Re: I rarely wait for the light to come on
Date: 2011-03-07 09:40 pm (UTC)