The information technology industry is infamous for frequently misbudgeting time by hundreds of percent. But really, the superset of this error applies to the entire domain of highly-structured desk work.
The reason for this is, blue-collar i.e. manual labour is typically WYSIWYG, and switching between tasks is easily explicit. However for desk i.e. "knowledge" workers, the high costs of switching contexts in memory is often overlooked.
Therefore, in general :
A : the time it takes to clear memory before pursuring a task, T
B : the time it takes to execute T
C : the time it takes to reload into memory whatever was being done before T, which needs to be continued after T
A + B + C = the proper budget to be quoted for any task
Effectively, sometimes 5 minutes of button-pressing requires a quote of 45 minutes, for example.
Model your staff like this, and you'll never misunderstand this part of their experience, again!
