Thanks—that’s even better separation than using separate accounts at the same bank. More work, but something I hadn’t thought of.
To further detail the exact amount of effort: I get paid once a month, so once I month I go in, look at what I’ve got, subtract off my estimate for everything else, leave a few hundred dollars of slush, and come up with some excess amount. I then go over the brokerage site and issue the transfer for that excess. At the same time, I review the state of the brokerage account. I think it’s pretty minor, and it gets my cash over to the brokerage firm where it can sit in a money market account. That pays a pittance these days, but it has been a significantly larger pittance than anything my bank would offer me for the last 15 years.
(And then you’ve got access to a variety of bond funds, so you can easily transfer the cash into a fund which matches your exactly risk tolerance. Or otherwise invest it. All useful things to be doing, which your bank does not usually facilitate.)