It's worth having when fixed (5)
I believe the answer is:
asset
'it's worth' is the definition.
I can't tell whether this defines the answer.
'when fixed' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'fixed' becomes 'set' (both can mean decided or determined).
'as'+'set'='ASSET'
'having' is the link.
Can you help me to learn more?
(Other definitions for asset that I've seen before include "A thing of value" , "Part of motor vehicle wheel" , "Holding" , "Seats (anag.)" , "Valuable person" .)