The cassette and chain on my bike don't last a year. Due to a bad knee, I'm riding a low power pedal assist Specialized Vado 5.0 SL EQ, and it eats the 12 speed cassettes and chains like I go through Fig Newtons. I clean and lube them religiously, but I still get them phantom shifting, and definitely longer in only 600-800 miles. I was shocked the first time it happened. (Please don't switch into the "eBiKeS aRe StOoPiD" mode now. I've heard it thanks.)