Depends on the qulaity of the strings. If they are made right then as little as a dozen shots helps them settle into the cam grooves. If they are not made just so-so then it may take upwards of 100 shots till the strands have all stretched to the same length and are doing equal work.

There's a couple ways to check them. When first installed you need to measure the a2a and brace height of the bow as well as weigh the draw weight. Mark the side of the cam with a pencil where it passes through the limb fork. If shooting the bow causes these to change then you don't have the best of strings and follow-up adjustments will be necessary.