It will vary for each account.
On each card, check your online account to see the dates of previous statements. Some cards always report on a certain date --the 17th, for instance --and others ramble around several days in either direction.
Make an educated guess as to when each statement is due to post again, and stop using the card 5-6 days before. Then pay online 3-4 days before you think the statement will post. Wait until your statement shows up online, and then you can use the card again.
Although it is possible to do this all by mail, it is obviously much simpler to do it online.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007