Electrical connections and light bulb sockets on 'cycles are much more exposed to the elements than automotive connections. To prevent corrosion, get a tube of Dielectric Grease from an auto parts store and smear a small amount on bases of light bulbs (like tail/brake/turnsignals) and any quick connectors.

Like the old Brylcreme commercial, "a little dab will do ya." I bought a tube back when I worked in an auto repair shop over 20 years ago and still have 1/2 tube left.

If a connection is already corroded, carefully spray with Electric Motor cleaner, plug and unplug several times to break up the "yuk." Then treat with the dielectric grease. WD40 will work in place of elec cleaner, but does leave a slight residue. Avoid getting elec motor cleaner on painted surfaces, btw.

Also, plain ol' Vaseline on a Q-tip or acid brush will prevent battery terminal corrosion and won't stain clothes like other greases. Clean the battery terminals, install the battery, and lightly coat the terminals, cable ends, and bolts.

(This is probably "old news" to many of the DIY-ers here. I'm doing these steps to the new S40 as I go..."an ounce of prevention, etc.")

we call it goose grease in the electrical trade
required on all Al. conductor terminations

We've had this discussion before. I used to think dielectric grease helped with conductivity. Apparently, I was wrong. It's actually an insulator to prevent arcing among other things. Works great on all the electrical connections.