The new practitioner is using blend mode and treating for up to 10 seconds per hair sometimes more than once if it does not feel dead. I am not sure what method the first used but she only took about a second per hair.
One second is enough to kill a thick hair like those you can find in the underarms. In medium or fine hairs, that time margin can be reduced.
Yes, I said well, I do not mean to pluck the hair with tweezers, but to a permanent hair removal performed with electrolysis, where the High Frequency current (alone or in company) predominates. The question is how much and where do you apply that HF current?
I agree with Michael, the axillas (or any other area of the body) should not require 3 1/2 years of regular treatments if between session and session those areas remain untouched.