Turns out that a lot of people I knew posted huge life updates that I completely missed out on. I asked them why they didn’t tell me and they were confused. They said the posted it on social media. I can’t speak for everyone, but I know a lack of social media meant that I have lost touch with old acquaintances completely. I have a few close friends and that’s it.
Maybe that’s an ok tradeoff to make, but it’s worth knowing that before getting into it.
Regarding life events: I quit all social media about 5 years ago[1]. People I care about know about that, and if they want to tell me about life events they do it with other means. Those who don't, they weren't really friends, just acquaintances. I am OK with that.
[1] with the exception of Linkedin, which I hate and never use, but I have been asked by people in my company to keep a profile for PR-related reasons.