I replaced all my woodscrews and few metal bolts with Torx.
Although I have quite expensive Bosch bits (with the hardened steel golden tip)I also have standard grade bits for €1,25 at the hardware store.
To be honest there is little difference, both don't wear out that much with normal use and I only have to replace them since I loose them sometimes
If you do very heavy woodwork with lots if force and the hammering type of screwdriver it might be a different story however;
The pro builders I talked to just say, I rather buy a box of bits for €1 a piece and replace the bits every week then buy an expensive bit to use for weeks. Why? Because if the expensive bit wears out or gets lost I don't have a replacement, while with the cheap bits I have an entire box.