If we assume nice open conditions, good weather, pretty flat, at what range would you allow players to start making perception checks to notice things?
Example: An enemy orc is on the horizon, lets say at what distances would you allow a player to check to see if they see something, and can identify it as an Orc:
DC 30 (almost impossible)
DC 20 (tough but a fair amount of people could see it)
DC 10 (you would have to have diminished senses not to notice)
As a follow up to this, there are a few abilities that give some extraordinary sight ranges. For example, the Eagle Totem Warrior, Eyes of the Eagle magic item, and a wildshaped druid as an eagle. So if you go with the 1 mile as the "extreme distance" noted for the eagle totem specifically, would you use DC 30 to start at the 1 mile marker for these types, or a smaller DC?