I console myself that I bought my V70 really cheap and it's a pleasure to drive so I shouldn't care about the petrol, but I know I've paid many times over for the car with the petrol costs.

Warning light to brim every time.
At least once a week.
Average 25k/year, 700 to 750 miles per tank.
90% Tesco as its closest and usually cheapest, plus I get the points.
Spend more on diesel than food in a week.
Something's got to be wrong......

A risk with tending to run close to empty all the time is that the reduced level of fuel surrounding the pump will not be keeping the motor cooled, so increasing risk of premature failure. I've seen this happen on a Ford where it would tend to blow the pump fuse when tank nearly empty as the motor was running hotter with a higher current consumption.

With P2 V70, you read of lots of folk running out of fuel when tank showing as 1/4 full. This is due to problems with the pump not transfering fuel from one half of the saddle tank to the other so the side feeding the engine is effectively empty.

Personally, I tend to fill the tank whenever there is an opportunity to buy fuel at a better price. Yesterday, had 10p/litre coupon for Morrisons which saved me over £7, so worth getting your moneys worth. My XC70 runs on LPG so I only tend to fill with petrol about once every 5000 miles so it's a bit of a novelty to use an old-school pump.

I just got back from filling my tank at the BP local to work. Normally it is 2-3p per litre dearer than the Shell local to my house, but today they were selling diesel for 119.9p, a 3p a litre saving!

10g - 45.46L every time based on "2 bars" on the fuel gauge.
Being a dinosaur OAP this suits me !

Bhowani
V60 T3

For my "everyday"needs I put in £15 every two weeks.This takes care of the majority of my motoring.If I decide to go somewhere I find out how far I'll be travelling[round trip distance]then add a little for a bit of leeway,then knowing pretty accurately my mpg I can figure out how much fuel-and therefore cost-to put in to do the journey.

Usually fill up as soon as the light comes on... when it got real expensive a few years back used to fill up as soon as I dropped below half-full , just so it didn't seem like I was spending so much at once (just twice as often).

I just put in £30 when I drops to 1/4 a tank which lasts most the week. Don’t see the point of filling to brim as it’s just extra weight

I fill to the brim once it gets to 1/4 tank, I don’t like running it any lower than 1/4 for the risk of clogging up the fuel tank etc.

I usually just put £20 in at a time only because I've got a few cars and there's no way I'm filling every one up.
There's a petrol station along from me that drops its prices one Saturday a month so that's the only time I put more in but I'm more often than not working that day so I tend to miss it.