I bought a high end Keyboard and mouse 3 years ago, still running strong no issues.
If you buy crappy keyboards and mice expect them to last a year or two tops.
TBH, an uber keyboard is over rated unless you use macros, then get an uber keyboard. For mice I'd look into logictech their software to customize the buttons is great.
I needed those extra buttons because my left pinky got tired of being used for control in wow.. like painfully tired LOL. So I use the mouse buttons for ctrl, alt, shift, and in wow, target selft + ctrl + alt. I had every spell linked to a hotkey.. LOL.