Do Cog building show up on a random time base or do they drop at a certain frequency? I have a task to defeat a sellbot building and I am having trouble finding any buildings at all.

It used to be the busier the district the more buildings there were. So switch districts.

Try Elm St in Daisy Garden or Sleet st in the brrgh

Hope that helps

Yes, definitely try different districts. If you're in a district that has recently had, say, a cashbot invasion, you'll find way more cashbot buildings than usual. Certain streets have more sellbots (which bring more sellbot buildings) than other streets (unless an invasion comes along and changes it temporarily).

The busier the district or the busier the street? I went to a district that had very few toons and the street that I went to had no toons. On this empty street I could only find one COG at a time. It would seem that the more toons are on a street the more COGs are on that street and possibly more buildings would be found.

The busier the district

Go to a busier district if you need tons of help. Go to a less busy district if you want to be by yourself.

Try a district that shows up "green" on the district page in your shticker book. Nuttyboro's usually ok. Nutty Summit and Nutty River are always busy, but you'll have a harder time finding tall buildings, cause they'll already be occupied by toons. If you just need sellbots anywhere, the factory is a good place. Do you need sellbots in a specific area (like Daisy's Gardens) or do you need some specific item from a sellbot cog (like the key to Daisy's Gardens from Minglers)?

I think it must be set by how many people are on the street, one morning I was searching for buildings and found a deserted street with many buildings,,when I was looking for a building to run alone the cog buildings all started to revert to stores without any help from toons till there was only 2 cog buildings left on the street.