I have done many locations multiple times. Including some locations three months in a row. Like most things, it depends on supply (of shoppers) and demand (of the MSC/Client). Nothing like those frantic e-mails, "Can you possibly go back there again? Last time we gave you $X bonus. Is that enough or do you need more this month?"
Removed - Post removed for violation of Posting Guidelines, naming client and MSC in the same post. Feel free to edit, removing the violation, then repost.