If you don't advertise it then it wont come. I don't do much to be honest but the course has paid for itself loads of times.
The important bit is id'ing the finish and knowing what is cleanable and what is restoration.
To be honest it is easy money and worth doing the cleaning course. I have done some restoration but find most don't want to pay for it.
"If you want to catch carp, fish in the right pond"