Longer than DS2? It is, but not by too much.
I didnt bother with the weapon customisation until about halfway through the game. I built up all of my Tungster, Semi-Conducters, etc and bought a Line Gun and Shotgun combo, focusing on damage and rate of fire. That thing is a beast up until the end of the game, then you start to take on humans, so I had to switch my gun game up. I ended up buying the Pulse Rifle with a Javelin attachment and focused mainly on damage and clip size.
Im the biggest hoarder when it comes to games like this, I never kept more than 20 bullets in my inventory and If I had anymore, It would go in my safe. If you carry too much ammo in your inventory, the necromorphes seem to not drop as much, but If you keep about 20 rounds in your inventory you will ALWAYS pick up more. I used to run out of ammo in DS2, but not in this game...not that its a bad thing though IMO.
I have about 1000+ rounds of ammo stored in my safe lol