Kilometres for me. It took some time to adjust when we first moved to Australia but it soon became second nature. Since we've been back in the UK, miles just feels wrong.
I would walk 804.672 Kilometers and I would walk 804.672 Kilometers more doesn’t have the same ring to it does it lol
My favourite take on this is when new roads are built. Engineers design roads in KM cost them by metre, build them by metre and tonne, and when they’re finished, the last job is the bloke who turns up with the road signs and has to do the measurements in miles.
Controversial for a 20-something, but imperial for me in most cases. I spent a lot of my time growing up with my grandad who enjoyed woodwork, metalwork, was trained to use a theodolite in the army before the metric switch etc. Imperial was his language. Metric is a good system and is 100% better in scientific fields, but imperial also has its advantages. It gave me a massive head start in mental arithmetic compared to my peers for example, with being able to calculate things that weren’t solely base 10
I got well into my 50’s before I realised why we were taught our tables up to 12 when I was a kid. I was 8 when we went decimal. The daft thing is, when my nephews and nieces did their tables in the 80’s, they were still arbitrarily taught to 12.
Full SI. Temperatures in Kelvin, weight in Newtons (*mass* is kilograms), moles for the amount of something (we all remember Avagadro's constant don't we?), candela for brightness...