Every Tarot reader will have a different answer to how frequently or infrequently one should get a reading. This can vary from reader to reader, and from client to client. Be wary however of a reader that will read on the same question within a few days of the initial reading.
My personal rule of thumb is that at least three weeks should pass between readings when the same issue / question is tackled. This is simply because I want the Tarot cards to change for the consultant upon his/her next reading, showing the growth and progress they have made since their initial reading.
This may not be the case for all clients; some of them only need a check-in once or twice a year, and that works for them.
Of course I am always available and most of all, I am grateful for every single consultant that contacts me. I simply wish to offer the best possible experience with the cards and also give the biggest bang for buck as well!