You're obsessing. Go buy gas, and for this good, physics-related reason:

Gas, especially gasohol, is hygroscopic. It attracts moisture. When it does, the presence of water does two things bad: 1) combines with radical impurities in the gas to form acids and sludge; 2) causes seperation of the alcohol component from the paraffinate (non-alcohol component, what others call "gasoline").

You gas is exposed to moisture by "breathing" due to temperature changes and diffusion. This effect is minimized by having the tank topped off all the time, which reduces the surface area of the gas exposed to air and the air volume acting as the "lung", venting your tank.

As your car sits a lot, some fuel seperation will occur while the car's parked. "Modern" gas isn't chemically neutral. It seems to go bad faster than it once did. Part of the reason is that adding alcohol lets the company make lower-quality gas and still not cause detonation due to low rated octane. They know the average person's not letting their car sit.

Factors in your favor: evaporative emission controls make the vent path to the tank tortuous; you live in a seaside desert. That's why you haven't had a problem yet.

And of course, a full tank enhances your ability to flee disaster.

... So, I drive mayyyybe 40 miles a week.

I get between 45-65 mpg hwy, and more like 38-45 in the city traffic I'm typically stuck in. Right now, I have half a tank -- and I live in Southern California, and can buy my gas at Costco.

I'd just go ahead and buy it now. You have half a tank, and the fuel capacity of a 2004 Insight is 10.6 gallons. So figure you would need 5-6 gallons to top off your gas tank. Even if the price of fuel changes by as much as 25 cents over the next couple days, you might save or lose a buck and a half or so.

You know, a lot of us wouldn't mind having this problem. Just sayin'. :)

What is the maximum price difference you expect? How much can you possibly save or lose? What do you think your time is worth?

You know the answer without doing the math,

Linksy-doodle.

You evil speculator! :-P

Our president said not to worry about the price of gas. Just make sure to put the proper amount of air in your tires.

Naw, they'd explode before lift-off. You'd fly but I don't think he has figured out how to control the direction you'd fly.

When prices are rising, you should fill your tank more often. I generally fill up at 1/2 tank when prices are rising.

It has the advantage that you will never buy a full tank at full price, only to see the prices start falling.

And when prices are falling, I do the opposite: let it run dry, and buy the full tank at the lower price.

Ditto what Radwaste said.

Burge.

er, yeah, what they said AND? You need to get that thing on the highway and clean stuff out. Your engine never gets warmed up, and full power, and as if you were sitting all day long and never moving, you'd get stiff. Say, once a quarter take a nice long drive up the coast and back. Oh, and? when's the last time you had fluids like antifreeze, oil and brake fluid changed? Just like gas, they can go bad, so you prolly want to talk to your honda mechanic.

Low miles can be good, but there are other things that happen.

Keep your tank full. If there is a glitch in availability, such as the 1994 Northridge earthquake caused, you'll be sitting pretty. I had two cars with full tanks and could drive normally when there was no gas locally for almost a week.

You are obsessing about less than a dollar a week of fuel cost for the amount you drive.

Time to break out the walking shoes.

> If there is a glitch in availability, such as
> the 1994 Northridge earthquake caused, you'll
> be sitting pretty.

I went to work that week, and a woman living in Santa Monica asked for a ride home. During the ride, she talked about her extensive preparations: Food, clothes, meds, batteries etc. So I asked how things had gone for her two days earlier when the quake hit. And she said "Well, I keep the stuff in the trunk of my car... And it was in the shop. Thanks for the ride!"

People drive to work in cars.

Here in Northern LA its pushing almost $5 a gallon. Last week Obama asked congress to end some subsidies for oil companies, it seems they have a power struggle going on right now.

I'm of the thinking Obama sees the need to lower gas prices at least some time before the election (regardless of whose fault), or he will lose voters, if for nothing else out of spite. This might come in the form of a subsidized gas holiday or something temporary that will push his poll numbers over until November.

So I say if you can hold out for a month or so until pre-summer (if that's possible) when America's planning vacations, and they've reached the "fuck this bullshit" tipping point. Thats usually when everyone in DC pulls together to keep poll numbers up.

Carmageddon

Not wealthy, nor burning money (not on gas, anyway). I think the use of "obsessing" was just a little bit of hyperbole, and not really meant derisively.

One thing to consider though: How long has the current tank of gas lasted? Maybe you could buy a couple gallons or so now and top it off again later?

I'm not much good at predicting prices, so I don't generally try. I remember years ago in the U.K. getting burned badly -- one day I went to the base bank and bought that month's rent money, £250 at about $2 a pound. Two days after that, the pound sterling lost about a quarter of its value against the dollar, meaning I took a $125 hit. I'd have been better off being late on my rent and paying a penalty if I'd known.

If you get 40ish mpg and drive 40ish miles per week then you only use about a gallon per week. Does it really matter if it goes up a quarter per gallon? A quarter more per week? Even if it goes up a whole dollar a gallon more, it only costs you an additional $4 per month.

Prices generally are higher during spring break. Gotta gouge the vacationers.

Gas prices usually trend to fall after spring break since crude oil is being used less to make heating oil and more is being processed for gasoline.

It always goes up this time of year.

What Radwaste said.

You don't use enough gas for it to be worth thinking about - and gas doesn't keep.

"If this is what you opinion is of an obsession, what's your term for somebody with an actual obsession."

"Obsession".

There are degrees. You knew that.

And now I wonder - have you changed oil in this thing?

Does that mean, "No"?

Because if it does, it's more serious to your long-term economic health than a dollar-fifty difference filling the tank the rest of the way.

Oil contains alkali and buffers to combat acidity, which corrodes engine bearings, and solvents to keep the engine's internal deposit balance low and stable over time. Both deplete with age. The ability to combat acidity diminishes faster in stop/go service because the engine spends more of its service life at low temperature, by proportion to its overall run time.

And this isn't obsession. It's how your car works.

And if you're reluctant to put gas in it, and it's out of warranty, those are signs it's not getting its oil changed. I hope otherwise.

From my experience, women wait until the red oil light comes on. Then the next time they see a man, or stop at a gas station, they ask what it means. Otherwise, they drive it until it seizes up and they have it towed.

"No, sillies, of course I do not do this myself"

Hey hey, I learned to do this myself after I got a car that I really enjoy.

We can't control gas prices.

We can control the temperature of earth.

Can't remember where I saw that - but thought it was cute.

Don't miss the wisdom of Randall Munroe, who, of course, has thought about this.