Estimate monthly parking costs.
Monthly parking is a threshold decision, not a rate calculation. The pass price divided by the daily rate gives the number of days a month at which the two are level, and anything above that favours the pass. Typical downtown pricing puts the break-even near thirteen days, which is why a full five-day office week almost always justifies a pass and a two-day hybrid pattern almost never does. Whether the pass covers weekends changes its value if you also park at weekends.
Break-even
Break-even days = monthly pass price / daily rate
Cheapest
Monthly cost = the lower of the pass price and daily rate x days parked
Not always. Some are access-only and oversold at peak, so check whether the contract reserves a bay. A guaranteed space is worth a premium if arriving late means driving on to find another garage.
Use your lowest typical month for the decision. A pass bought for a busy month and carried through a quiet one loses the saving it earned.