Check Credit Card Bills for mistakes

We always make it a habit of checking our credit card bill charges, on line, every couple of days, to make sure that no extra charges show up, that shouldn't be there. By doing this, over the last couple of years, we have caught approximately $400 in charges at various times that shouldn't have been charged to us and out of this $400, about $200 were things we had legitimately bought - but were accidently charged twice for the same thing. So it pays to double check.