preferably / ideally, if you can, you stay in the 'Now' all the time, like a zen master. Your normal state throughout the day should be of no mind. A watcher not a thinker. You should watch your mind, instead being controlled by the mind. Living in the present, not in past or imaginery future.
And thinking is just tool, just like your leg is a tool. You don't use your legs all the time. You use it when necessary. So, use it only to make intention / affirmations / visualizing, to give life its appropriate images to bring forth new experiences into the moment of Now, and to work with things in your moment of Now (not ten minutes from now, but right Now)
Now