I sat down and really thought about what I was getting out of each of the services and then decided if that was important. For Twitter it was pushed updates on things going on around me. I realized it was almost 100% noise. That was easy to quit.
Facebook had a bit more value, but was still 90% noise. I first eliminated all the noise I could through unfollowing and unfriending many, many people. Then all that was left was a few family members and FB Messenger.
LinkedIn was nothing to me. I've had this job for ten years now and I have no plans to find anything new anytime soon. That was an easy delete.
Like, it's not really a big deal to shut this stuff off, and it'll help you get back in touch with reality.
I never got on LinkedIn, and it has in no way hurt my career.
In my case I noticed the benefits within a few days. Surprisingly I never felt like I was missing out on anything, though it takes a little more effort to stay in touch with friends (a plus IMHO).