WHY DOES MY DOG CHEW ON MY DANG SHOES?

Okay, so my dog has never chewn my shoes befor, and i have left her alone for extended periods of time. Then, one day i come home and find she has my $680 shoes from Paris chewn to bits!!!! WTH???? I considered her being mad/upset at me but then i scolded her, and she seemed really ashamed about it. Then a couple days later my Guchi boots were completley chewed and slobbery!!!!! I take her out for a 1hour walk everyday and take her to go to " do her duty" right befor I leave my house, and i never leave her for more than 5 hours. She has fresh water and plenty of chewy of toys....what should i do? I usually make shure that my shoes are put away but i don't want to have to worry about it all the time before i leave! im so upset about my shoes and i don't understand why she is doing this! And im not shure if she'll turn onto something thats laying around and then ill have to give her up!!!!! I love my dog, but i am having issues with her chewing my stuff. And she was never taught to do this as a puppy and shes 3 years now! Help! 10 points to best answer.