I've done this for several years now. While I also do other things for Lent, this practice seems to make a difference in my day, but is also one of the more challenging tasks to follow. I often find myself clicking the Facebook icon on my phone without even thinking about it, only to close it immediately when I realize what I have done.
This practice makes me avoid reading most comments on posts, which by itself makes my life happier. It also gives me more incentive to skip posts that make my blood boil, let alone leave my own comments on them. Sometimes, I still cannot help myself, but I immediately regret doing so once my timer (which I set on my Fitbit) goes off.
Certainly, there are things that I miss out on because of this, but probably not as many as my imagination tells me. Now, if only I could use the time that I am saving more productively ...