the alternator belt keeps breaking
 

Hi all,
My alternator belt brokeabout 7 times in 2 years. Every time i take it to the shop or shops they always say they fixed and so it shouldn't break. the last time i took it was last week . It squeals for a little while then it will snap or burn out. I think it is the pully system but every mechanic says that it isn't . so now my car started squealing again already and i want to figure out the problem befor it breaks again . Does anyone have any idea what it could be........ Please help. I know enough about cars where i can fix somethings . So i am really getting tired of paying these people for doing a job that i know i could do on my own if i buy the proper tools. If i fix it though i want to do it right so it wont snap again. thank you