MSPs, how do you integrate ExSP Symantec.cloud into your practice?

Using the ExSP program, the Symantec Endpoint Protection Small Business Edition 20123 (Symantec.cloud) software is billed by distribution on a quarterly, after the fact, basis.

I am curious to know what other MSPs are doing in terms of:

1. Billing - How frequently do you invoice your clients (monthly, quarterly, annually)?

2. Services - Do you wrap up the charge in an existing service/support contract?

3. Usage - How do you track installations?

4. Renewal - a.) How do you know when your clients' subscription is up for renewal and b.) How do you notifiy your clients?

Thanks!