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.
Splitting hours and minutes into base 60 started with the Sumarians like 5000 years ago, passed down to the Babylonians, and just kind of stuck around. 60 is great because it has a bunch of factors - 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60 - so it's easy to split up into even parts. Apparently it's called Sexagesimal
A year being ~365.25 days long is simply how many times the Earth spins on its axis during a full orbit around the sun, because the Universe does not give a shit about being neat and orderly. Months and weeks are just figuring out how to manage it the best we can. Kinda dumb that February has 28/29 days though, like there's a bunch of months with 31 days stop hogging them all and let February have a couple more, assholes.