Here is a thing that hitting my head from a quite some time. What is the actual fame time of an average tweet or you can say the life span of a tweet? As we know there are millions of tweets getting tweeted and re-tweeted every single second.
Well its pretty hard to say. 15-20 minutes may be I guess.
If you are unpopular than 5-10 minutes maybe but that also depends.
If you are not a celebrity than your tweets life span in just 5 mins or maybe even less.
It depends upon popularity but mean time of tweet visibility for unpopular profile is 5 minutes.