Do unused monthly changes roll over?
No: the small changes included in the monthly fee are counted per month, and what is not used in a month does not carry over to the next.
Counted per month
Depending on the package, you get 2, 4 or 8 small changes a month. If you combine several modules, the monthly number is that of the largest module. What is left in a month is lost: it does not add up.
What this means in practice
If you know several small changes are coming, send them in the month they are relevant; there is no point saving them for later.
With Premium
With Premium, changes are unlimited: we work on one request at a time, and as soon as it is done, the next one can come. Premium's content writing and Facebook content come with a monthly allowance; the My requests page shows how much has been used this month.
Let us look at your site.
The quote form takes two minutes: package, add-ons, your company details. You see the price at once, and it commits you to nothing.