I will expect that there will be many opinions on this!
Some will recommend lubrication with engine oil, some with gear oil, some with an aerosol grease and some will say coat the coupling with grease! Some might even suggest a chain lubricant that ‘ sticks ‘ better. Like we Chainsaw chain oil
Lubrications will attract dirt and grit , some will say this accelerates wear.
However rusty couplings wear as well, and rusty is harder to dismantle to replace!
I would say if using oil, lubricate regularly to hopefully wash away the collected dirt as well as to lubricate. If your really keen before or after each use.
My opinion is it doesn’t matter what lubrications you use so long as you use one.
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