Quiet afternoon for me so I'll throw in a bit for you...
Lots of ways to find out and keep track of due dates etc - your broker, set alerts, websites etc.
Not all companies are equal when it comes to reporting requirements either. Qtly/6 monthly etc
As far as milestones go, read the announcements from whatever companies you follow and they'll usually have the set dates... then it's up to you to monitor, set alerts etc.
Very hard to monitor the whole market when reporting season comes around, best bet is to set alerts through your broker on those companies that interest you, that way you can be on the ball.
There is a raft of ways to find out information - google is good, make it your friend.