one of the best things you can do is get rid of any switches on your lamp and run a wire strait through ,so it touches to metal on the handle that you can touch on and of with your thumb ,like i have always done since i started lamping with a home made lamp ie,lr9.you will never have trouble with a switch breaking when your out and miles from the car .
lr9! Thats going back a bit! Good lamp in their day-used to have a 48w one before the halogen one came out.
Re the switch,i used a doorbell button,quiet and reliable.
yes good old sold lamps the lr 9 .i tried the door bell year