It is a common paradox in team management: we hear "we are short-staffed" and "we have too many people" almost at the same time, and both statements can be true, depending on the moment or the time slot. Dimensioning a workforce is not a matter of intuition; it is a precise calculation. The real difficulty does not lie in arithmetic, but in establishing correct assumptions (demand peaks, planned absences, required skills) and constantly validating them with real data.