Originally Posted by
Akihabara
Yes, typically that coincides with the announcement of being able to recline, use tray table etc. However, there are also cases where they announce but continue to be seated too given the "Captain has decided to keep the seat belt sign on ..".
To the OP's point, I was trying to think of what the cabin crew explicitly say or don't say regarding reclining and "takeoff"... I am flying in a few hours.. will listen keenly

Apart from putting the seats in the upright position before take off, I don't think there is any further instructions. So no clear instructions as to when you are allowed to use the seat controls, can't recall hearing any recently. But will listen more closely for the next couple of flights.