I was taught from C150 days to always pay homage to the undercarraige God.
By the way, It should not be "undercarriage down".
It should be "undercarriage welded down" in a fixed gear aircraft.
With retractables, it should be "undercarriage selected down", and your hand should not leave the lever until you can honestly say to yourself after watching the lights come on: "three greens, undercarriage down."