I've been reading few month back that official Twitter limit is 1000 a day including retweets. From our experience - we are using TweetAdder, so far each account posts around 220 tweets a day, 75% affiliate links, 25 quotes. Why so many tweets? To make more money of course. I 've never checked manually how many tweets posted on Twitter because TweetAdder reports it as posted. Min time interval 5-9 min. Many tweets with links and quotes are retweeted by followers. We are using private proxies - 2 accounts per proxy.
I've been reading also there is Twitter rate limit - 150 actions per hour (follow, unfollow, tweet etc). I think this is a key to answer op question.
Some of the accounts are getting suspended from time to time for unknown reason, then after email to Twitter it gets unsuspended. So far we did not loose any of our 24 accounts.