I am a software developer by trade for 19 years now and have the MX Keyboard and MX Master 3S. Very nicely designed products, love them, but the MX Master 3S left button started malfunctioning after about 18 months. I am very disappointed for a mouse of this price tag. In my whole career I have never discarded a mouse due to one of its buttons failing. Why would I buy a $120 mouse that I have to replace every 18 months when a $20 mouse would last multiple years. Fix this and you would have an awesome product on your hands.