At which point does a band stop being a hobby and start being a trade needing to register for SA?
When it is making money?
Pub bands would tend towards being hobby income as likely exceeded by expenses each year.
Tribute & function bands almost certainly charge a great deal more and would be into the trading bracket.
A subject that fairly regularly comes up on forums for musicians IME
What is the intention?
If the band is performing "with a view to profit" it would be a business, whether or not it actually makes a profit. This would mean going all out to get the best gigs, signing up with an agent etc, not to mention keeping proper records. On the other hand, if all they want to do is cover their costs (as far as possible), it is more likley to be a hobby
the intention is generally to buy as many new "toys" as possible :)
Right at the bottom, playing originals to noone in some grotty backstreet dive the intention is to be the next big thing/rich & famous. The reality for most is somewhat different, but there are a lot aboutsome making a living, most not.
Pub covers bands / weekend warriors - still potentially the grotty venues and cover expenses / pay for the next toy - grey but probably more towards hobby
Function / tribute bands - generally looking to make a bit of extra cash, though the toys could still put a major dent for the w/e warriors making it grey for them, but probably edging into trade in the majority of cases.
Thereafter most likely well over the line into trading