Hi alex.bernard ,
I thought to point out regular deoxidation of contacts will help in low resistance applications. Pure silver is known to tarnish, although a better conductor when not contaminated - some switches use a silver alloy to reduce tarnish formation of silver, especially in low-voltage applications, although the alloy will add a slight increase in resistance but may offer more consistency.
Ref. Cleaning & Protecting Contacts, Switches, & Potentiometers