I,know the spawn points, but the good spawns are so random I rarely see them. There was a wild Blaistoise I caught less than 100 meters from my front door last November. I know Pokémon spawn there now but I can't see what's around anymore.
Just frustrated because there are limited stops and all I can see is the garbage that spawns there.
So far under the nearby system has led me to one Lapras, and has caused me not to see dozens of good Pokémon that I never saw until they popped up on the screen.
Another flaw in both sightings and nearby is it gives no priority to rare Pokémon. I could care less about a pidgy or weedle when a Snorlax is nearby. Show me the good stuff first!