My grandma always put her Senior sheltie in a sweater (she's a rescue and was shaved down in her previous home, her fur never did grow back). Sable, the sheltie loved her sweaters so so much! My friend who owns iggies (italian greyhounds) also puts sweaters on her dogs, since they're always cold. I'll even put jackets/coats on my younger dogs when it snows. If they tolerate it, then why not (plus the sweaters are beyond adorable)