There is a link in the top post to the rules - I forgot to include it initially, my bad.
Copied from there (and edited for year):
Tier 1 Challenge
During the calendar year of 2024 (01/01/24 - 31/12/24):
- No bass gear purchases/trades whatsoever, be that amps, pedals, basses, accessories.
Tier 2 challenge (should you play other instruments, engage in music production etc)
- As above, but extended to your other musical gear
Allowances in both tiers:
- Strings (sticks, skins, reeds etc)
- Maintenance/setups that only involve work on existing aspects of your bass (ie no purchasing a preamp to add to it)
- If something breaks through no unusual intervention of your own, and is unable to be repaired, you may replace it.
- Educational purchases, ie tutorial books, lessons, anything that furthers your playing is permitted.
- If you have purchased something in 2023, you are able to take delivery of it within 2024.
- If you have put down a deposit on something before committing to this, which then requires a final payment within 2024, that single payment permitted.
Although not mentioned here, precedent has been set in previous years that unsolicited gifts are allowed. But it doesn't work if you get given money as a gift then you choose to spend that on gear. Also precedent has been set that decrees that the replacement of broken items must be like for like as near as practically possible - no abusing this with sneaky upgrades.
Hope that helps!