We have a 12 month old King Living sofa which has leather "puddling" on 2 of the seat squabs and also on the back rests. These 2 seats are the ones most used of all the seats as they have recliners. (We have a 2nd TV viewing area so I wouldn't think the seats are "over-used in any way).
Please find attached photos as follows
Photos 1 & 2 Seat 1
Photos 3 & 4 Seat 2
Photo 5 Back rest Seat 1
Photo 6 Back rest Seat 2