I am like may others on here, I had a vest at one time, then switch to a Wild Hare pouch and never looked back I love it. It will hold up to 100 rounds and I shoot a lot of 100 bird shoots so it works great for me. I have to say, My vest kept on shrinking one me so it only made sense to start using a pouch that hooked on my own belt.
Another thing you might want to consider is whether you chuck 'em in the trash at the end of every round or go back to the truck with multiples of 25 empties to take home for reloading.
I have started doing the latter and 100 is about my limit for lugging around in a pouch.
In a vest 25, maybe 50 at a stretch.
I got used to using a vest when I first started shooting. I have tried shooting without it, but just feels better with a vest. I would think you should use whatever feels comfortable for you. I also use a pouch with its own belt for the empties. Again, just what works for me.
I use a belt pouch and a vest. I like using a vest to keep shirt in place with a consistent mounting point but I don't like the weight on shoulders when vest pocket is full of shells so I carry my shells in a belt pouch.