Your Katya robot can work without a Wi-Fi connection, but in that case, it is not possible for you to use some of its features. Having a Wi-Fi connection provides you to make use of your vacuum with all of its features.
Katya robot vacuum box contains side brushes for left and right sides one for each. You can easily remove the old brush and replace it without using any screwdriver. Besides, you can find ever-updating information within the Simart Technology APP/APK regarding the expected life of the accessories.