When the random spending checking account is out of money, the random spending stops. Have the bills checking account automatically deposit a set amount weekly to the random spending account. In your budget, this looks like a weekly "bill" that you do the math in your budget for. Thus, every time you spend randomly you don't have to stop and recalculate your budget (frees you to spend as wanted), but at the same time limits your spending to stay in budget (when the random spending account is empty that's it until the next weekly transfer).
“When the random spending checking account is out of money, the random spending stops.”
A concept foreign to so, so many! ;)
I see this as a gimmick for the undisciplined but if it works, that’s great.
For me I charge everything and pay it off in full every month.
Sometimes there’s a surcharge for using the card, like at a restaurant. If I know that in advance I use cash.