I rarely do CORI jobs any more because I have too many other companies that I like to work with more. But throughout the industry generally a client has a location shopped once a month or once a quarter, with some clients having multiple shops done per month, sometimes at different times of day. How many shops are available in an area depends on how many of the client's locations are in the area. Most generally there is a rotation on shops and depending on the client you are allowed to revisit the location usually after 30, 60 or 90 days. I have seen rotations as high as 540 days and some 'only once ever' for some locations. I have also seen a few shops with no rotation at all.
I believe CORI is one of those companies that pays every two weeks. Industry standard tends to be 4-6 weeks.
One of the things you will note with CORI is that their shops start with a very low fee and if not taken, the fee on them begins to grow. It becomes a game of chicken--how high can the fee grow before another shopper in your area grabs the job? Where you decide to jump in and take the job depends on when the job is paying enough to be worthwhile for you to take it. Most companies don't play this game. They initially offer their work at prices enough shoppers find worthwhile to get their job board cleared and they then they bonus only the last few shops that nobody took in order to get them done.