The best time was yesterday or a year ago. basically anytime you can acquire more steem power you should. i regret not acquiring when steem was around 0.5 and i regret not being able to acquire more when steem was as low as $1.2 a few days ago but i did acquire some at these levels so its not all that bad. i have still to power up but i am satisfied to have that in control. i would like to get more so it means i wont mind if steem keeps going down for a few months it will allow me to buy some more each month.