Ok, this seems so basic, but I keep wondering if I'm playing right. How do you balance your portfolio? Is it by the dollar value or by the units held? For instance, as a Couch Potato, I'm supposed to be sitting at 50% VXC, 25% VAB, and 25% VCN. Which is what I have based on the current value of the funds, but following this wondrous market fluctuation, I am wondering if I should be balanced based on units held rather than dollar value.
As a complete newb/moron I'm not sure how I'm supposed to be balanced.