Personally I wouldn't treat a bag unless it's absolutely necessary and especially if it's not new. Most of my bags, even the oldest ones, have leather that is practically new or soft from use but not dry or parched, which is way beyond "lovingly worn". Out of the 20 or so older bags I have/had, I've only lightly moisturized one and conditioned/treated another because it really needed it. I look at a treatment as bringing the life back into the bag, not altering the leather if it's still in good condition. I also think Balenciaga informs its store and authorized retailers to advise against any sort of treatment or service to do so, since there are products that can alter the dye. It can also be a liability, even if it's a change for the better. I know people here will moisturize a brand new bag that was treated already by the manufacturer to get the veins/cracks out, which is fine but it's personal preference and isn't something a retailer wants to be responsible for .