Most newer model water bladders are made and or treated with anti-bacterials so it is not as big a deal as it used to be but that doesn’t mean you should neglect them. Make a habit out of emptying them out, hanging them up, and letting them air dry as soon as you get back. And don’t forget the hoses (an air compressor helps with these). Clean and dry keeps the gunk away and extends useful life.
By the way, I was never all that crazy about the way the water tasted in my Camelbaks. No matter how clean they were or how much baking soda I used I could always taste the plastic. So I tried a bunch of different kinds of bottled water in them and Evian is what finally did the trick. A little Gucci I know but it works.