My MBP keyboard degraded over time, only 2 years in. Started with WASD (hehe) and spread outward until nothing worked. I plugged in an external keyboard and soldiered on. One day I bootcamped into Windows and something went wrong. I got completely locked out because apparently the internal keyboard is the one and only way to get the boot menu. I understand repair would cost $250+. Very disappointing since my previous MB lasted 9 years.