playing long games does help in developing key skills like calculation, value of activity etc.. however i dont think i have the patience to play online chess. 15 min is just fine for me.
Online chess is working for me :)
Pdve, patience will make you a better player. Online chess gives you depth understanding of 30 moves in advance.

Pdve, patience will make you a better player. Online chess gives you depth understanding of 30 moves in advance.
wow. 30 moves? are you sure? not sure even carlsen manages that. or even kasparov.
I notice improvements from the time I play online chess. I have time to analyze and this is helping me improve. In my chess club I played only blitz and my improvements were very slow. I recommend to play a lot of online chess to everyone to improve.