I live in Montreal, Canada.
Here we use three different systems; officialy, we use the metric system, for example:
- road signs and cars are in kilometers
- the pumps calculate gas in liters
- outside temperature is indicated in Celcius by the medias
- only the metric system is shown in school
But, we also use the imperial system, which is the system of the English empire that we used previously (Canada is part of the Commonwealth as being one of the oldest english colonies).
For example, lots of my uncles and aunts (I'm 25) will talk to you about their cars doing miles per gallon, miles per hour, etc. They will also buy stuff at the store in pounds.
I personnaly weight myself in pounds and mesure myself in feet. That is not close to change... even if then babies are weighted in kilos at the hospital, and measured in centimeters, they also indicate the conversion on the official papers, otherwise the parents don't have a clue.
Also, I personnaly have trouble reading the inside temperature in Celsius... I know exactly how warn I like it, but it's in Farenheits... (even if we only calculate the outside temperature in Celsius, and nobody converts them to understand, not even my grandfather). Also, I have never seen someone calculate the temperature of the pool or spa in Celsius... Don't ask me if 25 Celsius is hot or cold for a pool, I really don't know !
And finally, we also use the American system. The american system is different that the imperial for some measures like "gallons". For example, an imperial gallon is almost exactly 4 liters, while an american gallon is 3.78 gallons... this is why it's always frustrating when you put windshield washer fluid in your car, and they sell you the fluid in 4 liters containers, but the damn US car's ww fluid container is only 3.78 liters ! You always have to carry the damn container because they is always some left...
Also, all the contruction is done in feet and inches. We produce the materials, lots of them, but none of it is produced in meters, because the main market is the US, so they just don't bother with our small market and produce everything in feet. This means that architects and engineers, even if they only learn the metric in school, must learn the english and american systems when in university. The same applies for a lot of people that do plumbing, mecanics, and even furniture.
However, the people here always use the same terms as before, even if the units have changed; for example, we will say "a pint of milk", even if nore it's no more a pint, but it's a liter...
Which system I prefer ?
Well, I don't really care... I find the metric system the best, but I would certaintly have problem purchasing furniture in centimeters when all my house as been constructed in feet.
I do like the feet and inches, because I find them conveniently easy to estimates, but when you start evaluating distances that are longer than the terrain my house is built on, I will say "300 meters further, turn left"... and will calculate in kilometers.
The thing is, if the damn US could convert to the same thing as the rest of the world (which will never happen, or perhaps never before China is the new superpower), we will be stuck with the three systems in Canada...