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.
Hahahhahaj, you were victim of my bad English. I meant a bag of beans! Hahahaha.
I was just giving an example of how you could have an intuitive idea of metric units by the using objects around you if you eventually need it.
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.