I found my long term T purely by chance. I had just moved to the city and was in crisis - I needed to see someone ASAP. I had called I don't know how many Ts in the phone book and was having trouble finding anyone with openings. I had booked two tentative intro appointments, but even they were at least two weeks away.
Then I called my Ts community center. The receptionist had gone home sick, and my T was inbetween clients so was manning the front desk. She also happened to have a cancellation that afternoon. I stayed with her for many years, and a decade later we still keep in touch after ending therapy with her we still keep in touch.