Hi Wa34937, the criteria for appointments at Mayo Clinic are complex and include many variables. Mayo Clinic has more requests for appointments than available openings. Appointments at Mayo Clinic are prioritized on the basis of medical need. Availability depends on the nature and urgency of the problem and Mayo Clinic's ability to help (as determined by a Mayo Clinic doctor). The complexity of the medical condition and, for less complex conditions, the availability of care closer to home are also factors.