I'm in the process of creating a presentation for my encap program. What would be a good recommendation to present to the potential client for how often the carpet should get cleaned on a maintenance program?

Every job will have a different requirement in regards to maintenance cleaning.

Experience will determine how often different areas should be cleaned.

Quoting for jobs falls into the same basket, not all jobs are equal in area, soil load, type of soil, etc;

The learning curve is huge, thankfully, encapsulation is making this curve smaller.

Do you have Rick's CMS Program ??

If not, I would suggest you purchase it immediately.

As Shorty said every building will have different requirements Best to get feed back from your clients as to what they want. Certain areas will need anything from weekly to monthly cleanings, while other areas may only need 3 or 4 cleanings a year.There is no set standard for how many times a area should be cleaned.
The big question is how clean do they want there building? Once you know that than you can build a program around their requirements.