Vehicle needed in one's job, usually (3)
I believe the answer is:
bus
'vehicle' is the definition.
(bus is a kind of vehicle)
'in one's job usually' is the wordplay.
'in' indicates the answer is hidden within the clue.
'BUS' can be found hidden inside 'ones job usually'.
'needed' acts as a link.
(Other definitions for bus that I've seen before include "Large passenger vehicle - small business!" , "Road vehicle able to carry many passengers" , "Public service vehicle" , "People carrier" , "Use transport" .)