The spending doesn't need to be exorbitant or overly "conspicuous." Just steady and purposeful. In a deflationary economy, having a lot of cash socked away is good, because it keeps going up in value. So, if the ruler has the biggest savings account, he can spend so as to essentially keep breaking even, I would think. But, of course, if we're not talking about a traditional monarch we'd have to think about the ruler's income, state property, and the ruler's relation to state property. If there's a lot of state property, and the ruler has access to it, then there's always revenue coming in.