Adopt a newbie

And when you play a game, time it.
The standard time limit for official tournament game is 2 hours.

So checking the game situation after two hours is a good way to see how your decks might function in the "official" environment.

When you play casual games without a time limit the game will often end differently than with the 2 hour time limit.

Then again, if official tournaments are of no interest and consequence to you, ignore the above