A recurring profile is optional on a Job Type Template. 

In some instances the recurring profile will be different for each individual job that you do, even if it is the same type of job that you are completing.

You would use the Recurring Job Profile on a job type of a six monthly inspection as it is always going to be done every six months. There may be instances where the recurring schedule would change for each job so it is much easier to manage the recurring profile on the job itself. For instance a cleaning job for one customer may be weekly and for another it may be fortnightly so it would be easier to have one Job Type Template for cleaning and choose the recurring frequency on each job when it is booked.