We quit maintaining a register when we went pretty much 100% plastic for groceries, gas, etc. (funny part is we use cash when we travel, we spend less that way). Worked fine, until...
Credit Union changed software. All of our billpay went to pieces. Double payments here, no payment there. Cost us about $2K in late fees and overpayments (of course, the overpayments were not losses, but fouled the budget). Wreaked havoc on our credit rating, too.
If my wife had not kept the paper, it would have been a worse mess. That alone showed us that the banking software geniuses, at least here in New Mexico (Schools in 51st place), are not anywhere close to genius.
We retire soon (four more working days till I qualify for group retiree insurance) - intent is to revert to primarily cash and handwritten checks. And, the smart phone is going to become dead, going back to the flip phone.
David
NM