I've returned a lot of MFF stuff back when I could order from FOS (and before the recent upgrade in products) because the leather wasn't nice, or the bag wasn't the right size, or it just looked different from the picture. I could always tell when I unwrapped the bag, so all the hardware was still wrapped and such. Eventually I stopped buying MFF items and focused on Legacy deletes.
For FP PCE buys or deletes, I've only exchanged Blush Haley because it had a wonky zipper and unevenly dyed back, and returned Fuchsia Rory (that was just a LOT of pink for me) and a Mint Basket Clutch (I have fibromyalgia and need a wrist strap at least). Otherwise I've been really happy with my FP
Coach purchases and deletes.
Recently, I've been having trouble with ebay purchases - a Coastal Blue Haley that was, in my opinion, too squished in transit to be considered 'new' anymore, and the Graphite Turnlock tote. The shoulder straps are too thin for me and hurt my shoulder. (I have fibro.)
But the tide seems to have turned on that - I just got a lovely Coastal Blue duffle very recently, and I've been very happy with it, and have been eyeing both another duffle and just ONE LAST HALEY I SWEAR.
My collection is probably close to 40 bags now. Eek!