A past practice is defined as an existing practice sanctioned by use and acceptance, that is not specifically included in the collective bargaining agreement. The first consideration is whether the matter is a condition of employment.
Conditions of employment are personnel policies, practices and matters affecting working conditions.
If a matter is not a condition of employment, there is no obligation to bargain over it. Over time, a condition of employment can become a past practice but simply because something has happened over time does not necessarily make it a condition of employment. That is, if a certain action is not a condition of employment, consistently performing that function, even over a protracted length of time, does not make it a condition of employment and, thus, subject to bargaining. If something occurs on a daily basis, a past practice will occur sooner than for something that happens only quarterly. For example, the daily use of microwave ovens in a break room for five months is a past practice.