Accrual expiry "take it or lose it"

In an Accrual Allowance, there should be an option for it to expiry at a specific time so employees won't be able to accumulate the hours. 

Example: a Work Profile accrues 2 hours per week. We would like to ensure that the 2 hours expire at the end of each week (i.e. users cannot build up the 2 hours from previous weeks, it is 'use it or lose it').