No one is mentioning gnucash and I think that's beautiful.
My partner and I used a spreadsheet from Google docs "budget template" or something. Moved on to gnucash after we wanted more features. I love it now, but it was a struggle to learn. Also a clunky interface. Also way more complex than we need. But I did once track down a tiny error in one of our bills, saving us a fraction of a dollar after hours of cross-checking!!
(I do love it though; the tradeoff is that we don't have to do repetitive manual entry and duplication of info. Instead, we have extensive notes on how to accomplish what we want!)
Yep. If it's 9:22:45, then rounding to 9:23 is more accurate than 9:22 anyway.