Rule 17 Reservation of Objections

Once you object to a piece of evidence during a trial, you don't have to keep objecting every time that same evidence comes up again. Your first objection covers you for the rest of the trial.

This saves time and avoids the need for lawyers to repeat themselves over and over. It also protects your right to raise the issue later, such as on appeal, without worrying that you lost that right by not objecting again each time the evidence was mentioned.