Now I know I'm sad .... - steveb
... after having filled up at the local Shell and paid, on returning to the car to make a note of the mileage and number of litres etc to keep the running total on the fuel consuption... to see grandma in her Toyota Corolla doing exactly the same thing on the other side of the pump...!

Sad Steve
Now I know I'm sad .... - HF
Or maybe grandma is a reader of the HJ site! You never know...

Happy HF
Now I know I'm sad .... - cockle {P}
Don't feel bad I do the same, always have. It might seem sad but it's surprising how you don't notice if fuel economy drops off slowly. Keeping a running record once helped me to notice that my carb was losing tune slowly, but surely, and was costing me a drop in economy of nearly 20%, so I reckon those few seconds making a note saved me quite a few notes of the blue kind!

Cockle
Now I know I'm sad .... - daryld
Airlines and road hauliers do it..and so do I.

I travel the same route everyday, 86 mile round trip, in my 2000 Seat Arosa diesel. I got an average of 69MPG for the first 10,000 miles (using BP Diesel), then 72MPG for the next 10,000. I then changed to Shell Diesel and now get an average of 79MPG. I have maintained this consumption and the car had covered 51,234 miles with an oil/filter chnage every 5,000 miles.

Keeping a fuel log should help me diagnose any potential problems as well.

So do not feel bad about keeping a fuel log--makes perfect sense!
Now I know I'm sad .... - edisdead {P}
My mates have a right old laugh at my fuel logging habits.
However, I am heavily reliant on my car (public transport out of the question due to rural location) and just as you say daryld, the first sniff of a potential problem and I want to be aware of it. Keeping a fuel log is a good way of spotting problems in advance. Also helps with the household budgeting.

It would seem a large number of backroomers feel similarly, given the popularity of the recent 'MPG...' thread:
www.honestjohn.co.uk/forum/post/index.htm?f=2&t=11...4

Ed.
Now I know I'm sad .... - SpamCan61 {P}
Count me in as well...I'm even sad enough to have an MSexcel spreadsheet with a chart of mpg vs. time (complete with rolling average); fuel bought in current tax year, distance driven in current tax year and since buying car...blah blah.
Now I know I'm sad .... - frostbite
Perhaps belonging in the gadgets thread..... I am delighted to leave all the calculation and logging to the computer on my old Scorpio.

Even better is its ability to convert all the litres into mpG!
Now I know I'm sad .... - CM
my grandad used to do something similar.

He used to make a journey from Hampshire to North Wales quite a few times a month. He used to note distance, time and speed (not sure he was that interested in mpg). Quite why he measured distance is beyond me as the two places he was travelling between hadn't moved.

But then he used to take notes of rainfall each day!

 

Value my car