No that feature yet. Generally I do not like time tracking features, as it puts extra burden on developers. But if there is more votes, I will consider to add that.

I think we don't need that, because we can customize issues. I've just created "Time spent" field which has type "period".

This is a good start point for effort tracking. A full time tracking may also need to include some advanced features such as burn down chart based on estimated time/time spent, gantt chart, etc. I will leave it open for others to vote before diving into this feature.

My main thinking is that instead of having to update a field each time, a much quicker and more efficient way is to do !timespent 1h, etc.

Some of my clients like to know how long a task takes, and to itemise the invoices by the task can make for a very long invoice (we're talking multiple pages at times), at the end of a month.
This way, I can invoice by tasks (i.e. total number of hours) and then they can actually look at the ticket to see how and when it breaks down - writing an update and logging how long it took.

That way, they've got a log, and I've freed up hours of time (honestly, review meetings are not fun).

Duplicate with issue #57