If we go over our allotted messages, are we automatically billed?

Some basic information about how messages work, first.

The allotment of messages are as follows:
- Direct: 1,000 per month
- Basic: 3,000 per month
- Plus: 7,500 per month

Month to Month billing:
If you are on a month to month plan (credit card only), that is how many messages you have in a month. If you go over, you need to purchase an overage bucket. Unused messages in a month roll over to the next month.

12+ Months billing:
If you are on a 12+ month plan, the monthly amount is multiplied by the number of months in your account plan license.

Example: A Basic Plan for 12 months has 3,000 per month x 12 = 36,000 messages/segments.

With the above 12 month plan, you have access to all 36,000 segments immediately. That means you could send 18,000 in the first month and then have the rest sent over the following 11 months in your license (or any other breakdown of that math).

Answer to the question "If we go over our allotted messages, are we automatically billed?"
No, we do not automatically charge you if you go over your allotment. 
If you go over your message allotment, your account may not send your messages, so it is best to top up your account with Overage Buckets ($99 per 5,000 segments).

Also...
Overage buckets are NOT per month. They simply add to your account totals. Think of them as "topping off" your account plan allotment. 

That means:
1. Month to Month accounts can have a surplus of messages/segments they can pull from if they go over their amount in a month.

2. 12+ Month plans can have a surplus of messages/segments they can pull from if they go over their total amount allotted for the length of their license.
-- Using the Basic Plan for 12 months example above:
If you purchase 1 overage bucket ($99 per 5,000), you would have 41,000 messages/segments for the 12 month period.

-- What most clients do is start with their regular license, then watch their volumes. You can always purchase buckets later if you see that your monthly averages will make you go over your plan allotment.

Related Article: SMS Messages and Segments - What are they?