String:
Im in the UK and was born in the transition imperial > metric.
The result is im an odd kind of hybrid unable to adopt one system fully.
Temperatures, metric. Fahrenheit means nothing to me
Weights, im still using pounds and stone.
Measures, litres although pints when it goes to drink.
Distances, imperial. I understand miles/miles per hour but km/h means absolutely nothing to me. The only exception in diving is i use meters as my gauges and tables are all meters.
Pressures im definately bar as opposed to psi.
I guess folks that use a mixture of measuring systems are probably in or from the native-English-speaking world. What's really interesting is how the combinations differ.
I grew up in the U.S., with Imperial of course.
Spending a large chunk of my life in the military, I learned to use metric for distance measure... that's what all NATO military maps are in (though I seem to remember that contour elevations are in feet in the States)... and I could sure judge 2,000 meters as the maximum distance I could hit a tank-size target with my tank main gun. I still tend to express distance in meters, rather than yards.
I use (and think) mph when driving in the States, but km/h here in Europe. We've got two U.S.-spec VWs, and I don't even see the large mph speedometer figures anymore... just the smaller km/h.
Heights in cm or weights in kg don't mean anything to me... it's feet/inches, and pounds (we don't use no stinkin' stone). I've sort of developed a feeling for degrees C, but F is still "natural" for me... I have to think of C "benchmarks" and what they're equivalent to, then adjust from there using a very rough 2-to-1 ratio (zero C = freezing, 21C = room temperature = about 70F, and 33C = 90F... when I consider it officially "hot").
I know that 2,000 meters is about treeline in the Alps for backpacking, and that any elevation below that may be iffy snow-wise when making skiing reservations.
Diving? I learned Imperial... that's what all our family's gauges are... and that's what I think in. Twelve meters depth? I can't picture that. But 40 ft? Oh, yeah. Freaks European divers out.
And a full tank fill is 3,000 psi, even if the guy filling it is thinking 200 BAR.
--Marek