Durations are specified with positive integers and unit specifiers.
Unit specifiers include the following:
A duration of 1 week is specified as
A duration of 1 week, 1 day, 1 hour, 1 minute, and 1 second is specified as
Whitespace surrounding the value and the unit specifier is not significant.
"5d" is equivalent to
" 5 d ".
Not all properties taking a duration allow all unit specifiers. For example, milliseconds are not allowed if durations smaller than one second are not permitted.
Some properties limit minimum or maximum durations.
An unlimited duration is specified using
unlimited (recommended for readability) or