If one side of pulley's are worn different because of alignment or just normal wear, it might help add to the hours the belt will last.
---or it just might accelerate the wear causing early demise.
But I think it would be quite insignificant.
Being Left handed, and parting my hair on the right side of my head,
at times I'm so confused I don't know if I scratching my watch or winding me ass
And thinking what Ambush said, all bets are off for those on the udder side of the planet.