Here is my experience : 6 months ago I created 90 Facebook accounts. Today only 50 of them are active. All other 40 required friend recognition or ID verification and they were lost.
All my accounts use private proxy, always the same IP for each account, maximum number I use is 2 accounts per IP.
I never post in more than 30 groups daily. For many accounts I post only once or twice a month. I use the Account Actions module of Massplanner to keep things normal. Still:
FB has an incredible algorithm to detect patterns, if you post the same link with more than 3 accounts, all accounts get blocked.
FB is starting to use photo verification at every share. It is basically a pop up that asks you to check pictures of whatsoever to make sure you are human.
For new accounts, one report can bring the account down. Meaning: if one member thinks your post is spam, you are done when he reports you. Considering that 1000s see your posts daily , this is very likely to happen.
Mass Planner is an awesome tool, but FB is getting very tough.