For example,
60 seconds = 1 minute
60 minutes = 1 hour
24 hours = 1 day
7 day = 1 week
29-31 days = Month (approx.)
365/366 days = year
It's like for the imperial measurement of distance, where 1 mile = 5280 feet...
Edit: just to clarify, I'm more or less keen towards any consistent, decimal-based measurement systems like base-10 or base-12.
Haha no problem, your English is waaay better than my Portuguese! I understood what you meant and that's the point I was trying to make too. I don't need to do any conversions to figure out what a mile, gallon, etc. is because I already know, just like you already know what a kilometer and liter are.