Hi Barbara,
I think you are talking about the manual check function.
If you are using the current version of Payables (and if you're not, you should be at AP8.1B 100512) and leave the print check unchecked, then the next time you go into creating a manual check it will stay unchecked. You have to click on (Print Check) to enable printing the check every time you enter a new manual check.
If you forget to assign a number on a manual check (already hand written or internet payment) you will be prompted to enter #.
After the entering the checks you will also see on the batch listing whether on not the check has been assigned a number or unassigned to be printed.
If you are entering numerous manual checks at month end, I presume you are aware that you don't have to print a check after entering every manual check but could simply highlight the batch (after entering all of your check details) with all of your month end manual checks and click on print. Print will just print the unprinted (unassigned) checks, and leave all of the other assigned checks alone. And then post the batch.
Brian