Honestly I tried so hard to always wear a helmet since I started playing this game but at the end of the day I always feel like I'm way, way better without one.
I currently have 10 brand new exfil with visors and ears protectors + moded fast mts sitting in my stash, I was like aight it's the end of the wipe let's give it a fair chance since it doesn't matter if it coast a shit ton of money.
The moment I go in a raid and put the visor down it's just awful, It trully feels like it puts me in a massive disadvantage by drasticly reducing my visibily, it lowers my ergo by a shit ton and reduce the hearing. And It almost never saves me, I even got one taped by an IA scav on a brand new visor on factory, I also get killed by a grenade fragment that went trough a full team exfil.
What is the fucking point of theses things I honestly don't get it, they are just a huge waiste of money and makes everything worst from my experience, I always have better encounters without helmets/visors because it makes ADS so much quicker, you also turn and move faster.
If you spend 150k on something that have a tiny chance to save a 600k loadout, you are better loosing your loadout from time to time because of a headshot that could be tanked by a helmet than investing on helmets every time, you will actually loose less money by loosing a loadout.