In relation to the asset allocation process, an investor may have a certain percentage of the assets invested in specific categories. As aspects of a person's life change, might it be appropriate to change the percentage of assets held within the different categories? In other words, if someone had originally placed 20% of total assets in the bond category, is it possible that at some point the same investor may elect to have 35% of total assets invested in bonds? Why . please explain in detail ?