Cal Newport's "Digital Minimalism" addresses this common use-case scenario.

1) Remove the apps from your phone and log out on mobile browser, making each future login a concentrated intentional effort. (You can leave Messenger if that might be used for emergency contacts).

2) Use www version only.

3) Choose a time when you're going to sit by your home computer, and use social media for some pre-determined time slot, let's say 30 minutes.

The social networks are very good at serving this use case - showing most important content first, and relegating the junky stuff further down the feed. This way you won't miss any baby photos or wedding announcements, but will be spared from your uncle getting into a heated political discussion.