The RoHS directive upset the world of electronics by banning the use of lead, which was part of many alloys.
Previously, components were only re-tinned in rare cases, for example, to remove gold from component legs to make the soldering more reliable.
One of the main virtues of lead is the much lower re-soldering temperature of electronic boards than that of pure tin (around 215°C instead of 240°C) and the absence of whiskers, a monocrystalline structure that develops on pure tin soldering over time which can lead to short-circuits.
Re-tinning constraints
Benefits of re-tinning the component
Re-tinning checks
