One of the many reasons to do household accounting. It's not even about making/keeping a budget, but simply about knowing where your money goes. It's a shame that many solutions are in turn also subscription based, so I don't have any good recommendations (I use YNAB Desktop, which was killed off a few years ago and replaced with a SaaS solution that's always increasing in price). But having insight into how you spend your money is such a powerful tool, it's worth doing even if it means manually entering stuff into a LibreOffice Calc workbook.