I go to my friend's lfs whenever he informs me he has new fish. His fish may be a bit expensive but those fish are often in excellent health condition and are rarely available in other lfs too.
The second one, I just go there to buy my equipments from time to time. I don't buy fish there but I'm planning to get those so-called albino rummy-nose tetras for investigation. The price tag is thrice more expensive than the original strains which put me in doubt of its actual identification. The thing is you cannot see their actual coloration in the lfs' tank.
The third one-I rarely go there. Unfortunately, they just sell angels, Lake Tanganyikan cichlids and goldfish. None of which catches my interest.
The fourth one-I go there at times but rarely buy anything. The point is their equipments are outrageously overpriced and the fish are given very poor water conditions. They are not what they used to be.
Couple times a month, usually a Thursday because that's when the fish come in. I just stop in to see if they have any feeder shrimp (got to get them as soon as they come off the truck or they are gone!) or to pick up frozen food.
Most of my stuff comes from on-line stores and Aqua-bid.
really depends on several factors...
may visit all of them in 1 day, or visit some a few times a day, or may go a week or 2 without even stopping by. but usually stop average maybe 1x a week...