I think it is common to check that all the charges are valid--since there is a lot of credit card number theft around. But I think it is uncommon to check that

I think it is common to check that all the charges are valid--since there is a lot of credit card number theft around. But I think it is uncommon to check that they are the correct amount--instead you eyeball the numbers and don't do further checking unless a charge seems unreasonable.