1. A method of leaching polycrystalline diamond, comprising: providing a polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions in which a metallic material is disposed; positioning the polycrystalline diamond table in contact with a leaching agent to at least partially remove the metallic material from the polycrystalline diamond table; periodically or substantially continuously measuring a concentration of at least one constituent of the leaching agent during the act of leaching; determining a leach depth of the polycrystalline diamond table at least partially based on the measured concentration of the at least one constituent of the leaching agent; and leaching the polycrystalline diamond table to a selected depth at least partially based on the measured concentration of the at least one constituent of the leaching agent.