I'm a child of a mixed up time when it comes to measures and the likes. I am feet and inches tall, stones and pounds heavy, when it's cold outside, it's below zero degrees, but when it's hot, it's in the 80s.
I learned small measurement in mms and cms, so have no real idea of how big an inch is, but long distances are thought of in miles (and petrol is bought in litres to go into a car which reports how many miles per gallon it's getting).
Now and again, I'll need to try & recall how many chains there are in a fathom, or ounces per metric tonne, and typically call on the services of a search engine. That used to be searching for something like:
... where we'd normally get taken to a site in the results, which has a wizard of its own to do the calculation. Often times, the reason I want to convert something is because I'm already doing a calculation and I just need to know the ratios involved...
Which is why I love the little innovation that Live Search introduced:
Right at the top of the results list, there you have it - dead right this is useful :)