its all fun and games in the 1st year (well also depending on your cleaning regularity)

something else to consider are spare parts, mops, tanks, brushes, sweepers all will kaput overtime ( not mentioning deterioration of battery)

recently bought from taobao for my xiaomi ones, work as good as new again instead of forking out for a new unit and runs twice better from the bigger battery. anyway as some others mentioned depend what you want. want mop, want vac only or auto suck/empty bin etc all types also got