Validate Support Case Duration

Due to the multi-tasking nature of our Support Dept, we rely on them to enter an estimated Support Case duration, rather than start/stop a clock or use other time tracking features. This works OK, but we occasionally have instances where an employee will inadvertently enter the duration of a Support Case in hours instead of minutes. For example, they will enter 15 instead of 0:15, resulting in 15 hours instead of 15 minutes.

This doesn't happen often but at a 60x overinflation of the duration, the data errors can have significant effect on our metrics.

I would like to create a workflow that checks the Duration field for each Support Case. If the duration entered exceeds 60 minutes, a dialogue would ask the user to confirm their entry or go back and fix it.