I sight all my rifles using the maximum Point Blank Range method. For instance, if the smallest thing I'm shooting is a squirrel head, say 2", then I sight it for the maximum zero distance possible while never being more than 1" high, so if I aim at the center, I'm guaranteed a hit out to whatever distance it falls 1" low.
The ONLY exception I would make to this is a dedicated target/competition rifle for shooting known, specific distances.