if you have a one-year lease on your factory, then the long run is any period longer than a year since after a year, you are no longer bound by the lease. No costs are fixed in the long run. A firm can build new factories and purchase new machinery, or it can close existing facilities. In planning for the long run, a firm can compare alternative production technologies or processes. Land would be an example of a long run fixed cost. As you pay off the land the amount becomes zero which then becomes a long run fixed cost of $0