I've had landlords who would deposit checks with inconsistent timing -- sometimes several weeks after they received the check.
This results in a situation where the amount of money you have available to spend might be $rent lower than you actually think, unless you've determined whether the landlord has cashed the check or not. When I was the one writing the checks for an apartment I shared with my also-just-out-of-college roommates, that check was pretty big, often >50% of the value of my checking account.
While I'd appreciate the extra interest that I'd earn on that money sitting around for an extra few weeks, I'd rather have the certainty of knowing how much money I actually had.
(If the bank could show an effective balance, where the check is shown as a pending transaction, I suppose that would be fine too.)
That's why one records the check amount in a ledger kept electronically or physically with the checkbook. You will then always know what you have even if the pesky landlord waits 3 months to cash a check. It's old school but works flawlessly for one person.
(Dunno if banking apps have the ability to record written checks then automatically reconcile when those checks clear. It'd be a nice banking app feature but would reduce revenue obtained from overdraft fees, on which banks gorge.)
For a couple, one needs the has-the-checkbook? mutex to write new checks. Each spouse having a credit card paid down monthly reduces the mutex contention for negative cost (considering float and rewards, ignoring credit-only prices).
Supposing the above fails from time-to-time, there's a defense in depth approach: If you write those checks from a margin-enabled brokerage account, anytime you make a mistake you self-fund the overdraft. This can be useful if the checks you write in a month are small relative to your margin collateral. This can also be useful if one occasionally needs to write a check for larger, one-off purchases where it'll take a few days to move the money around to satisfy the check. This is conceptually nice because a negative checkbook balance stops being haltingly terrifying if you know a regular paycheck will land before some checks clear. Do not trigger margin calls on yourself!
