Books have been said on this topic, and the contention and interchanges about where the "hot" slots are located in a casino are still ongoing – over sixty yrs after slot machine games were first placed in gambling houses.
The quintessential rule is that the best slots were located just inside the main doorway of the casino; so that fun seekers going by would be able to see jackpot winners … be inspired to come inside … play. Our conviction is that this is definitely no longer the case.
Many of the mega casinos nowadays are super-colossal complexes … now you can’t see inside from the sidewalk, so there’s no longer a reason to put the ‘loose’ one armed bandits close to any entrances or exits.
An additional traditional rule is that loose slot games are installed on the major aisles inside the casinos, again so that more potential players could see winning jackpots and be energized to play. Notably however, we find that this also is not a universal rule any more.
What casinos found over the years is that people walking down the busy aisles were frequently on the way to somewhere else. If they played the slots at all, they would simply put in their loose change because they happened to be walking by. Win or lose, they would very often not stop to keep playing. And the very last thing a casino wants is for someone to win a jackpot by playing only a few coins and then not stay to put it all back in!
These days, casinos are constantly changing their philosophy about where to place the loose slot machines.