I have been handling Twitter Management for my clients from last 4 years. I used to schedule messages in bulk for the couple of weeks for the whole day to be delivered at specific intervals. I have managed two company handles plus one additional handle as a third party to promote company's products and ideas. I can give you the third party handle here @smilinggardens, you can check this account still has about 1850 followers. We always tried to keep only relevant followers. I keep on un-following spam followers, spammers, non-followers etc at regular intervals. We stopped posting in this account after December. But we keep on posting on company's authorized accounts till March 2015.