Maintenance and blade replacement schedule

What is the blade replacement schedule?  Do they need to be replaced on a specific interval or simply when performance deteriorates?  Any other regular maintenance?

The cutting blades will wear out as working hours accumulate, and the degree of wear depends on your grass conditions, working frequency and usage scenarios.
We generally recommend replacing the blades every 100 working hours or earlier to maintain ideal mowing performance. Please wear professional protective gloves while replacing blades to prevent cuts to your fingers.
You can also check the consumable timer in the App to view the current wear status of parts and replace them following the corresponding reminders.

Thanks!  I’ve found it in the app shortly after posting the question here.  I see that the brush needs to be replaced, but I don’t see it available for purchase.  Is it eventually going to be available?

Pro tip, they currently have their blades on sale for 25$, and the upgraded 6 blade cutting disc for 77$ as well as a 20$ off coupon on accessories.