I live in a very cold northern state and from mid-September to April I wear my Acorns at minimum 10-12 hrs on an average day. In the "old" days of Acorn products (like 7 or more years ago) their slipper products lasted many years. Now I can tell you that if you wear them as much as I do (and I do wash them once a month) you will get approximately 1 year or less out of the fleece mocs with a plastic sole. Two chronic problem areas: their seam at the toes will come undone and I've tried to have them fixed at a shoe store but they said they wouldn't/couldn't do it/wasn't worth it. Every single pair I've owned in the last several years has developed this problem within a year. Also, the lining on the inside will wear a hole or 2. So why do I keep buying a new pair of Acorns every year? Because I haven't found a washable slipper that is as attractive, comfortable and warm as these. I feel I can justify the annual purchase given the abuse these slipper take. In the "old" days when they made the moc soles from leather, the toe seams stayed intact much longer. My husband and I have been wearing only Acorns for 30 years. He doesn't wear his nearly as often as I do, and he has had the same pair for several years now. Also, I am a female with shoe size 9. I find the L is a tad too small but the XL is a sloppy fit (and this proves that the toe seam will come undone whether my toes are pushing against the front or not). Last year I got the XL, this year I will go back to the L.