Recommended · for some experience
EEVblog #317 - PCB Tinning Myth Busting
Why people recommend it
Dave Jones measures how much solder over exposed traces lowers resistance, finding roughly a 50 percent cut on 1 oz copper; cited for high current PCB traces.
In their words
The benefit is 25 - 50 % reduction in resistance as per this video. Again, it will depend upon the copper thickness and lead thickness.
Whiskeyjack on electronics.stackexchange.com, May 2019. CC BY-SA.
EEVblog #317 - PCB Tinning Myth Busting (14 minutes youtube video)
Daniel on electronics.stackexchange.com, Jul 2014. CC BY-SA.
Dave Jones found it reduces the resistance of 1oz copper by 50%, so the equivalent of 2oz copper in resistance (and higher in thermal capacity, which might come into play for surge currents).
Spehro 'speff' Pefhany on electronics.stackexchange.com, Apr 2021. CC BY-SA.
