If done right, they would staff at 150% of demand. That extra 50% is to focus on cross training, process improvement, and the unscheduled work that comes in unplanned.
The next year you stay 150% staffed, but you need less people because of the skill and process improvement.
The cycle repeats, and after 5 years or so you get higher output with fewer people than you started with.
I've seen it work. It fails when some id–t thinks they can simply let 10% of the people go after a process mapping session.
Originally posted by @lco+18wPLZfH.