BBC Covers Drivers Saving Fuel (in the UK)

[Arragonis]

For 95% of the UK population a garage is no more than a couple of miles away so that would work. It would make it much harder to work out if you were saving anything though.

Most people just fill up to save time usually along with the weekly supermarket shop run.

[piers.singer]

This is very true. Back at home, in Sussex, there are two petrol stations within 400yds of my house. I tend to fill up only as much as I need for a journey because I don't use the car all that much (plus I'm usually skint), tending to walk or cycle into town instead.

In which case, it all comes down to a matter of convenience. As for the numbers actually adding up, I should think that it's marginal at best.