Mosquitoes lay eggs in standing water and don't venture very far from where they are born. No standing water near your property and the likelihood of mosquitoes drops drastically. Maybe there was some sort of standing water near the other property.I moved into my current house in 2008, and it's maybe 10 blocks from my other house and for some reason, almost no mosquitoes despite the fact that I had them over there. No idea why.
That's how they keep mosquitoes away at Disney World even though it is built in a swamp. All the water features there are in constant motion so no breeding grounds.