For the cost these work for me! First time to try "cushion pad" type.  Really like canvas best - were out of - so tried these.  I wear a 6.5 US & these fit good enough, slightly loose as a slipper should be & I have wide feet.  If yours are really narrow may not be satisfied.  don't expect a long-lasting fit as fabric / support will stretch & give out from heavy usage / wearing (as in walking to mailbox through grass wet or dry, walking to the ponds to feed fish, dogs, cats, possums, birds, etc or light gardening in the evening, painting a wall, ping pong or darts.  If that is how you wear your slippers (like tennis shoies or flip flops), then for me, I get about 9-12 months but really can't say for sure.  That might add up to 2-3+ years of walking to TV room, pool, sauna. I don't think one can wear out the exterior sole unless maybe walking alot on concrete or stone.