It's customary for Saul to do one turn after another (5)
I believe the answer is:
usual
'it's customary' is the definition.
(similar in meaning)
'saul to do one turn after another' is the wordplay.
I cannot really understand how this works, but
an anagram of 'saul' is 'sual' which is located in the answer.
'turn' could be 'u' (a 'U-turn' is a kind of turn) and 'u' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for usual that I've seen before include "Drink repeatedly taken" , "Normally done" , "Normal, customary" , "Typically occurring" , "Customary - customary drink" .)