We aim to keep 3 months in liquid savings (are currently at 2.6, but will be back at 3 months by the end of the year). We put absolutely every expense that we can on rewards credit cards, which we pay in full each month. I have an app on my phone where I track every penny in and out, so I always know where we stand with spending, but it doesn't match up with the actual checking account because the expenses are largely paid on a credit card. I also keep an eye on our checking account balance to make sure we can cover everything, check it a week before our mortgage hits and the credit card is due, and anytime we have excess I put it into our stash (at this point we're paying down 401k loans we stupidly took out when we bought our house, but another 2 years max and that excess will be going to after-tax investments).
Depending on where we are in the month, the actual account balance varies wildly. I looked back 90 days and it was anywhere between $1500 and $9300, averaging around $5000 usually. But, we are in a HCOL area and our mortgage is $4000. I can't wait to downsize and not have the clown house anymore, but it's probably going to be a few years before we pull the trigger on that...