On a campaign, there are three cardinal resources: time, money, and people. Only time is finite. How a candidate/campaign chooses to deploy these resources (especially time) says a whole lot about them and their vision.
Money is soooo important to be able to run a strong campaign, especially in this crazy long primary. Traditionally, most candidates spend the majority of their time speaking to wealthy donors to make sure they have the funds to keep going. (2/)