Create a recurring appointment that automatically schedules every four months.

From the customer's location page, click the Create a new... button and select Work Order

On the Billing tab add the service description, adjust the price, if necessary, etc.

On the Schedule tab, select the tech.

Select the frequency Tri-annual.
Select the week of the service, in this example the service will be the second week.
Select the day of the week, in this example the service will be on Tuesday.
The Select Day(s) must match First Service Date. Otherwise, you'll have two appointments the first month. In this example, November 12, 2019, is the second Tuesday.

Click the Save button and you have a series created in that customer's Work Orders tab. This example shows a tri-annual series starting on the second Tuesday beginning in November. 

The system generates approximately a year's worth of appointments. As the newest appointments are completed the system appends the end of the list with additional appointments so you never have to remember to create more services. 

See these articles for creating other Work Order frequencies:
​How to create an Annual Work Order Series
​How to create a Seasonal Work Order Series
​How to create a Semi-Annual Work Order Series
​How to create a Quarterly Work Order Series
​How to create a Bi-Monthly Work Order Series
​How to create a Monthly Work Order Series
​How to create a Weekly Work Order Series
​How to create a Daily Work Order Series
​
​