I think 50K miles is a bit pessimistic. I've never changed the serpentine belts at less than 100K miles, and then it was still good enough to keep in the car as a spare. And I've never used any conditioning. Now the old V-belts was a different story - they didn't last very long.serpentine belts are all of synthetic construction and a good quality dressing will not soften it nor shorten its life of about 50k miles on average.
I don't think a panty hose will work anymore on the serpentine pulley system? On the V-belt system you had a deep V in each pulley which kept the panty hose on the pulleys, but the pulleys on the serpentine system is basically flat.a spare belt or two pairs of panty hose:thumbsup: