I understand this and I use all of what you just mentioned. However, unless you check your account online very frequently and verify every transaction, you still could miss errors, mistakes, and unauthorized charges. Also, no matter how much you check your account, uncashed checks will never show up in your online balance. Since both my wife and I use the same account and make frequent transactions (Gas, groceries, atm, resturuants, shopping, automated billings such as water, electric, mortgage, etc) it's not always easy to just scan online and make sure every transaction makes sense or is posted for the correct amount. Keeping a seperate record and balancing the check book is really the best way to verify that what the bank has as a balance is correct.