Have you been losing stitches when crocheting in the round? Most likely, the cause is improper joining. It can be confusing for new crocheters to determine where to insert the hook to join double crochets made in the round. It is helpful to remember that when you are looking at the front of the double crochet stitches, the loop is to the right of the post. Don’t make the mistake of joining the last stitch to the loop of the second stitch instead of into the beginning chain-3, which as you know is the first stitch of the round (unless otherwise specified.) Hopefully these photos will clarify it for you.
When you join correctly, your stitch count will not vary. You can also utilize a stitch marker until you get used to finding the proper placement of your join. Simply place a marker into the third chain of your beginning chain-3 at the time you make the chain-3. Then, when you come around to the end, the stitch is obvious with the marker in it.