I had a car seat screamer. The only way we went out is when DH was driving and I sat in the back seat with my nipple in her mouth (not ideal for safety). It was awful and debilitating.
We turned DD forward facing at 1 year. Bought her a new carseat at the same time. What a huge relief. She stopped screaming. She stopped throwing up from screaming. We could go out and no one was overwhelmed with stress hormones. We all started to relax more and have fun as a family.
This was before the recc turned to 2 years. Even still, I would do it again at one year. Not being able to go out or being flooded with stress hormones when you do isn't good for health either.