When sad, leads companion to this joint to find company they can rely on (4,4)
I believe the answer is:
blue chip
'companion to this joint to find company they can rely on' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'when sad leads' is the wordplay.
'when' becomes 'chip' (I can't justify this - if you can you should give a lot more credence to this answer).
'sad' becomes 'blue' (similar in meaning).
'leads' is a charade indicator (letters next to each other) (some letters go in front of others).
'chip' put after 'blue' is 'BLUE-CHIP'.
Can you help me to learn more?
(Other definitions for blue chip that I've seen before include "Highly prestigious" , "Of the highest quality" , "Reliable financial stock - highest value gambling counter" , "Stock regarded as a reliable investment" , "Of high value" .)