As expected in what you do, keep hearing you are to follow strange echo (3,3,3,6)
I believe the answer is:
par for the course
'as expected in what you do' is the definition.
'keep hearing you are to follow strange echo' is the wordplay.
I cannot really see how this works, but
'keep' could be 'fort' (I've seen this before) and 'fort' is found within the answer.
'are' could be 'a' (short for 'are', historical unit of measurement) and 'a' is present in the answer.
an anagram of 'echo' is 'heco' which is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for par for the course that I've seen before include "Normal" , "72?" , "Typical" , "achievement that seems full of holes?" , "Standard" .)