Just how long can a wooden flute be played at any one time? Will overplaying it (like…a couple of hours) result in something disastrous? 
I’ve had my Cotter since 2002…but rarely do I play it beyond an hour each day as I’m forever tormented with assignments by my dear professors.
If the flute is well played-in - like your Cotter, having been played for an hour a day for 2 years, there should be absolutely no problem to play it for any length of time.
Some sessions last for many many hours and as long as the player can last, the flute will 
Just take it apart afterwards and dry it well.
After all, these things are instruments and are meant to be played.
Jeroen