It's helpful when one's committed to particular position (10)
I believe the answer is:
assistance
'it's helpful' is the definition.
'when one's committed to particular position' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'one's' becomes 'I's' (Roman numeral).
'committed to' indicates putting letters inside (to commit can mean to imprison).
'particular position' becomes 'stance'.
'is' inserted inside 'stance' is 'sistance'.
'as'+'sistance'='ASSISTANCE'
(Other definitions for assistance that I've seen before include "Support" , "Help" , "Aid" .)