MPG for those interested

[Lord Voltermore]

Whilst I can understand  that many will want to monitor their fuel use , and other expenditure , in great detail and accuracy , I have never felt the need to constantly monitor it  down to the last drip of fuel or how I spend each penny .
 
While there is truth in the old adage "Look after the pennies and the pounds will take care of themselves".  I have perhaps been fortunate (or naïve in thinking ) that  having sufficient pounds left in the bank each month,and an awareness of  roughly how much I am spending on non essential luxuries  (which includes a newish Jazz and fuel spent on recreational trips) is enough for me to know whether I  am living within my means.

Would I really change my driving habits  knowing I am really only getting 60 mpg  rather than the 62 mpg  shown on the fibometer?  ?  Nope.  My bank balance wouldnt change.   The  Fibometer  is  accurate enough to encourage me to moderate my driving style  to increase mpg.  And I have spent many pounds from my bank balance on a relatively small hybrid car to minimise the environmental impact of my recreational use of the car. 

[5thcivic]

I agree absolutely with everything Voldermore says. I remember 50 years ago with my first Mini having a green notebook in the "glovebox" calculating spend and mpg.

Still find it interesting from an engineering, spec sheet and mathematical view to see what people calculate.

Everyones's driving styles, geography, traffic jams and temperatures will be different, checking manufacturers claims independently is always good.

[Downsizer]

All cars are less fuel efficient at higher speeds for obvious aerodynamic reasons, but in the Jazz hybrid it is particularly noticeable for engineering reasons. In view of the current world shortage of oil I think it would make sense to introduce a national 60mph speed limit. It was done before and the economic costs in lost time would be minimal. It would also have safety benefits.

[Jazzik]

I’ve been tracking the fuel consumption of our last four cars on "Spritmonitor" (https://www.spritmonitor.de/en/) for about 18 years now—out of curiosity and to compare the fuel economy of these different vehicles under various conditions.
It really takes no effort at all; it’s very simple, especially with the app.

[coldstart]

Keeping detailed records not only shows how I'm *) adapting to a new car, but also warns me early if there should anything be amiss!

*)  I'm always amused to read about "the car settling in" after a few thousend miles...
Well, that might have been a truism in the nineteen-sixties?!? - With modern cars and high precision manufacturing it will be more likely the human component "settles" and gets accustomed to the new car than otherwise

Addendum:
What model year was your last car exactly, where the user manual told you to get an engine oil change after the first few hundred miles?

[Jazzik]

What model year was your last car exactly, where the user manual told you to get an engine oil change after the first few hundred miles?

That was a long, long time ago...
But this is what the owner's manual of our future plug-in hybrid says:

Break-in Period

● The powertrain needs break-in. It is recommended that this be done within the first 2,000 km in HEV-ECO mode by smooth driving, instead of high-speed driving. The following practices can effectively prolong vehicle service life:
● Avoid flooring the accelerator pedal when starting and driving the vehicle.
● Avoid speeding.
● Avoid emergency braking within the first 300 km.
● Do not maintain a high or low speed for too long.
● During the break-in period, the proportion of HEV mode (with the engine involved in working) must not be less than 50% of the driving mileage.

In practice, this means the petrol engine needs to have run for at least around 1,000 kilometers to properly break in. For convenience, many dealers advise setting the car to HEV mode right from the start to ensure the engine accumulates sufficient running time.
Following the break-in period, the engine oil and oil filter are replaced (free of charge at our dealership) at a mileage of between 2,000 and 3,500 kilometers.

The brands and vehicle categories that still require a mandatory "break-in service" involving an oil change today fall roughly into three groups:
1. High-performance divisions (sports cars)
2. Motorcycles (broad industry standard)
3. Specific plug-in hybrids (PHEVs) from China
Like BYD (with its DM-i technology)—where the internal combustion engine often acts as a generator and must be capable of kicking in while cold.