I have 4 of these, one on each floor of my house. I recently replaced the oldest one because the battery life has dropped to 0 after about 2 years of normal use. I thought I would just put one on each floor so I then bought 3 more instead of running out of power after cleaning 2 floors before needing another charge. My house in town has 4 flights of stairs and I have to vacuum the stairs every other day because my dogs shed. The device works well when fully charged and is easy to clean after use. Small and manoeuvrable enough especially for cleaning. Not to say they are "disposable", but ultimately the battery will hold less charge and the device will get a little louder with age. I will continue to buy this product because it does what it promises. Much easier than pulling out a full size oreck to build stairs.