The plastic part inside this latch broke, and I wanted to print a replacement. I was genuinely surprised at how straightforward it was!! This is my first draft: it fit and worked fine! I made a second version with a few cutaways around the corners, and that was the final draft. (I forgot to take a picture of that one.)
There are lots of awkward overhangs, and I was having a hard time figuring out how it could be printed (a) in a good orientation for the stresses and (b) without supports. Then I remembered: we can just use supports!! I usually try to design so that they aren't needed, so I almost never use them. But wow they made this easy.
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!)