Watch out when saying something like 1.year in Rails. The result is not a Fixnum and can cause unexpected errors when the receiving end expects a Fixnum.

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While anything from seconds to months are Fixnums, a year is a Float in Rails -- when called on a Fixnum itself:

>> 10.seconds.class
=> Fixnum
>> 2.minutes.class
=> Fixnum
>> 24.hours.class
=> Fixnum
>> 28.days.class
=> Fixnum
>> 9.months.class
=> Fixnum
>> 1.year.class
=> Float # Boom.

While they are technically correct Show archive.org snapshot (a year is almost never exactly 365 days), even 1.year.to_f won't return a result that would justify always using floats: 31557600.0 is just the same as 365.days.to_f.

Note that saying something like 8.5.hours will be a Float (for somewhat obvious reasons).

Rails 4

Introduced by Rails 4 accurate date and time measurements are provided by ActiveSupport::Duration. It mainly supports the methods on Numeric.

>> 10.seconds.class
=> ActiveSupport::Duration
…
>> 1.year.class
=> ActiveSupport::Duration