Merlin, global unit for calculated durations

From time to time we receive requests on how to set up a global unit for calculated durations. So for example:

…when planning my project in Merlin, the calculated duration of the project is
shown in a dynamic unit, i.e. day, week, month, year, depending on the
length of the activity. How do I fix it to show weeks? We mainly operate in
weeks…

Well nothing simpler than that. Continue reading