system
Given the following post, respond as if you're commenting on Reddit:
human
[Batman] At what point in Batman's career did each of the respective Robins join up?

For that matter what about Batgirl and the rest of the Bat-family?
gpt
It is not an easy thing to answer.  For example, the current Batman has only been crime fighting for five years, but managed to go through three Robins (one of whom died and was reborn) and have a ten-year-old son who is the youngest Robin with one of his adversaries.   You can never tell how the current pan-universal threat will rewrite the universe.  Some fair it better than others.  

So this is very general:


* Dick Grayson gets adopted somewhat early in his career.  
* Barbara Gordon becomes Bat Girl around the same time.  Sometimes even before Dick joins, though rarely.  
* Jason Todd, sometimes, comes around and gets adopted after Dick graduates to Nightwing.  
* Tim Drake enters the picture after Jason gets killed by the Joker.  Often portrayed as forcing himself onto Batman while the latter is recovering from the loss of either Dick or Jason. 
* Damian Wayne comes in after.  Sometimes he comes in as Tim decides to go solo.  Sometimes he comes in to be the Robin when another Robin (Dick) has to become the new Batman.  By this point Batman is usually well established and experienced.  


These tend to be the most reality resetting resistant of the Robins/Batgirls.