If customers take on average 10 minutes to serve and arrive randomly at a rate of 5.8 per hour, then with one bank teller working, expected wait is 5 hours. With two tellers, 3 minutes.

A fascinating Twitter thread that starts with this arrestingly counter-intuitive fact about queuing, before expanding it to consider how freelancers can manage their productivity.

TLDR: With irregular workloads, you need a lot of slack in the system to avoid huge backlogs.

But read the whole thread.