If not now then when?
"Chess is life" - said once Bobby Fischer.
I would agree to the extent that chess has it's logical rules that allow one to be a winner if he thinks clearer, calculates deeper, evaluates positions realistically, has resistance to outside disturbance, controls emotions etc. "Survival of the fittest" - as it is in real life. In addition, in a chess game you cannot lie, flatter, bribe (I am not talking about the organisational moments). If you lie or bluff, it can be easily refuted and demonstrated on the board using logic.
For me it has never been like "oh, I will prepare to this later on", or "I will study this variation next time". For the chess game there is only NOW in which you need to act. If you cannot do it now, you will probably find a thousand of excuses not to do it later. Every game is a fight for life and death - that is the only way you can motivate yourself to think and find the ways to win or survive, without postponing your development to the "unclear" future. You miss your chance - it is gone.