often asked question, and you are likely to be flooded with many conflicting theories.
But tensioned leather saddles are not baseball gloves, horse saddles or hiking boots.
Tensioned leather saddles need a particular treatment or you can very easily shorten their usable life.
I find it best to follow the advice of the manufacturer.
MAINTENANCE, REPAIRS, SPARE PARTS

Now let the regulars all promote their special treatments. It will get very confusing.
Or just get a small tin of Proofide and follow the manufacturers advice.