There are two approaches to estimating the value of most of the properties you will encounter.
The comparables approach looks at recent sales of comparable properties in order to determine the value of your property. The capitalized income approach looks at the income from a rental property and what an investor would pay in order to receive that income stream.
Whatever your ultimate plans for a property, I recommend that you use both approaches, even if they result in different values. Future homeowners or flippers may be competing against investors, and vice versa.
Being able to calculate the probable value of a property to a competitor may give you a bidding advantage.