Each product code starts with a company prefix, which is expanded to a full product code. So, to choose the right company prefix length, it's important to think about how many product keys you'll need. By creating the appropriate company prefix, you start an annual subscription and become a member of GS1.
Still no idea how many you will need in a few years? Don't panic: you can always order an extra subscription to a code package if you ultimately need more identification numbers than initially anticipated.