After regularly taking orders I expected what's left (7)
I believe the answer is:
residue
'what's left' is the definition.
(I've seen this before)
'after regularly taking orders i expected' is the wordplay.
'after' says to put letters next to each other.
'regularly taking' means one should take alternating letters.
'expected' becomes 'due' (similar in meaning).
The alternate letters of 'orders' are 'res'.
'res'+'i' is 'resi'.
'resi'+'due'='RESIDUE'
(Other definitions for residue that I've seen before include "Material left" , "balance" , "Something left over" , "It remains after other parts have been taken away" , "What remains of something" .)