Duration function optional

For job type templates duration is a required field. My company inspects multifamily properties and our inspection on average takes 45 minutes per unit. Because the duration is required, I have it set to 45 minutes but if we are inspecting more than one whoever is scheduling must remember to edit the duration manually to ensure enough time is allocated to the job. If this required field could be made optional we could simply drag to the duration of time we need and avoid potentially forgetting to do this.