If I remember rightly it isn't how many you join per day it's how quickly you join them as to whether you will get blocked. Maybe set yourself a target of so many every few hours to prevent yourself from getting blocked.
from my experince
if u have a old active facebook accont
u can join as many as u want
but if the account is new
join only few with huge time gaps
basicaly u need some good fb accounts with some pre-activities
How old is considered old? Is one week enough? Just sharing one or two posts to the wall each day. Is it ok?
What do you think?
No, not even close. I posted nothing but wall updates 12 a day for a month with my bot and posted no links at all. Just joke pics. After a month tried to join a few groups and every account needed photo id. They have clamped down hard now.
It depends on the quality of your fb account (age, other activities, like/comment/share/reported of your posts received). It's safe to join 10 groups a day for new account. I've joined over 50 a day without a problem for quality accounts.
From my experience the younger the Facebook account the slower you have to build up.
Supersafe would be adding 2-4 groups per day with like 4 hrs in between. Just make it look natural to Facebook, so keep in mind what a 'normal' person would do. Ofcourse there is no such a thing as 'normal' behavior on Facebook but suddenly start adding 20 groups per day is def not. Like some stuff or play a Facebook game to make it look real. After a week you can do more and build up. It depends on your time, I mostly go supersafe but this might be too slow for you. If you have a few accounts you can also treat one supersafe, one medium and one risky. This way you'll discover your limits fast.
Good Luck!