* Size field: an estimation of how long you think it will take to get
it done (not counting review time, just execution):
* small < 1 day
* medium < 1 week
* large > 1 week
We have the "Points" and "Actual Points" fields for this. "Points" are
meant to be any unit of time appropriate for a given trac component, and
are the field for the estimate before work begins. "Actual Points"
specify the units of time the ticket actually took after completion, for
evaluation of estimate accuracy/drift/multiplier.
Popular choices for units of time for Points are "minutes", "hours", and
"days".
https://trac.torproject.org/projects/tor/wiki/org/process/TorAgileProcess