Logical Log Backups.

I'm having trouble finding a solution to a rather simple question. If you are backing up logical logs to tape, what happens when the tape fills up? Obviously you would not want to write over transactions. Do you need to guess how fast the tape will fill up and swap them out once in a while? If a archive is made I understand that the logical logs before the archive are not necessary to restore, but what happens if the tape fills up before an archive occurs? Thanks for any advice, Tim