Most general purpose Torx screws are T20 anyway; it's pretty much the 'middle' and default Torx size, much like Pozidriv 2. I don't really mind having to change

Most general purpose Torx screws are T20 anyway; it's pretty much the 'middle' and default Torx size, much like Pozidriv 2. I don't really mind having to change bits if that means I get the benefits of a good fit and enough torque. For woodworking and DIY I use T20 80% of the time. T15 15%, and then rarely T10, T25, and T30. I installed a pair of window sill screws with wall anchors once that had a T40 head; great torque and no cam out! Torx really shines in those applications. T9, T8, T7, T6, T5, etc. I've really only encountered on hard disks when dismantling them for fun. Not something most people would need. So for Torx most people are set with a supply of T10, T15, T20, T25, and T30 bits. T20 is really the only one I wear out (or lose) more than one per year of. No one knows what that weirdly numbered T27 bit is for, but I guess it's good to have just in case.