Guys, as the year closed, I ran mental math and figured that over last year I spend close to 50 hours on the phone, helping clients, discussing options, etc. None was billed. Even at 1/2 billable time, that's over $2,000.

With that preface; does anyone have anything they're willing to share publicly or PM about language used to communicate the need/benefits of simple remote and phone support for residential clients on a subscription type basis?

I currently don't offer service or support plans, nor have I ever billed for phone support.
Back in the day, it used to be 1-2 minute conversations that usually resulted in service call and/or upgrade/replacement of old gear.

Now I find myself supporting clients remotely (VPN, C4, OVRC) where conversations are taking 10-40 minutes and more often than not the issue is corrected while on the phone.
I don't want to just start sending a invoices (yes, it's my right; yes, lawyers do it all the time).
I would like to communicate with clients first; offering monthly plans, which might include discounted time, etc. but which must have limits on # of hours per month/quarter/year and spell out that onsite visits are still billable (whether discounted or not).
I don't want to reinvent the wheel.
No, I'm not going to contact an attorney.
No, I'm not worry about someone 'misinterpreting' the agreement and suing me for all I've got.