The most important thing is to get the right type of bits, for the type of screws in your market. All bits wear out and should be considered as disposable in today's market. I have been using Bosch blue, for carpentry work, and I have only worn out one so far in two years. A day to day jobbing tradesman will do the same amount of work in a week that i have done in two years. Torx are something else.
Personally, I have even had quality square drive that wear. Unless you are prepared to pay for a Snap-on-tools driver (megabucks) you can and should expect wear and the need for replacement; unless you are a very occasional user.
The other issue I have come across is bits that just don't fit right. I estimate that 80% of the time, people are trying to use the wrong bit. 20% of the time it is a cheap low quality bit issue. As I said before, I know of at least 3 different types of cross head screw driver bits.
Even with slotted screws it is important to use the correct size of bit to get a secure job done. Yes you can use a smaller size flat driver bit, but the chances of slippage are higher.
Another thing I have learned is to avoid bit sets if you want the best quality. Bit sets seem to be a jack of all trades and master of none. Personally I believe that the single tools (not sets) are a better choice, even if they do seem to be not so good a value.
For my own use my hobby is cabinet making. I use the Bosch bits for my power driver, and for hand drivers I have two cross head drivers, on for large (also ok down to for electrical plug fittings sizes), and one for really small screws, maybe m3 and smaller. I have three drivers for slotted screw. One large, one medium and one electrical.
Seriously, you should get drivers to meet all of your needs in a good hardware/DIY store (OBI, B&Q), Lidl/ALDI, or Screwfix. And you probably only need 3 of each kind maximum.
If you are working on computer or mobile phones, you do need specialist bits, like torx, star, etc. Again, I would avoid the multi tool kits, and buy the dedicated drivers that you need. I have bought multi tool kits and only ever used two bits out of twenty, and these were not great quality, the dedicated two tools would have cost the same, but been more reliable friends.
With regard to lifespan. I can buy a set of 10 identical bits for 5 Euro, or a top of the range driver for 50 Euro. If 5 Euro set of bits will last me for 10 years, I need to think of the other tools (or beer) I could buy with the other 45 Euro.