I think it really depends on how much you run, what climate, and how much water you like to drink when running. I wasted money on an expensive hydration vest, and ended up rarely using the vest and mostly just using the special 8 and/or 16oz bottles carried on me either in a run belt or arm band.

I live in Northern California and am a minimalist runner. I mainly run early mornings on mostly shaded trails, and a 16oz bottle lasts me for 15miles (I don’t need water on <7miles normally), so a fancy hydration vest was a waste of money and felt really uncomfortable. The only times I’ll wear it is if I do anything >20miles or if I run later in the day when it’s warmer. I also make sure I have plenty of water in my car for post-run, too.