There are literally 25 sizes of Torx bits (the star shaped ones), plus some variants ("security", plus, ttap, ...). That's actually one reason people complain a

There are literally 25 sizes of Torx bits (the star shaped ones), plus some variants ("security", plus, ttap, ...). That's actually one reason people complain about Torx compared to, say, Robertson. Unlike with Philips, you are less likely to use the wrong bit by accident though. One of the worst things with Philips is that there is a very similar and very popular drive called Pozidriv, and you sometimes find both on the same piece of equipment, adding to the confusion. Using the wrong driver kind of works, but with a good chance of stripping the head or damaging the bit.