Review on 🔧 High-quality Replacement Accessories Kit for Roborock E25 E4 S5 S6 E20 E35 C10 S50 S51 S4 Xiaomi Mi Mijia, Set of 10 Accessories (2 Main Brush + 4 Side Brush + 4 Filter) by Harish Soto

I have S4 (not S4 Max) and hard floor, replacement filter and main brush work without error after 106 minutes of continuous cleaning (single session). For some reason my S4 no longer makes that grinding noise when spinning like before and seems to be quieter. Not sure if this is related to replacing the new main brush. The main brush hair appears to be finer than the OEM brush. The filter looks like an OEM. I also cut out the nylon mesh as recommended by some here. He hasn't used the side brush yet so can't comment on that, but can't think of why it's not working. Q: When do I need to replace the main brush as the original main brush still looks good after a year of use?