I’ve had this question on my back-burner, too. My biggest issue with established budgeting tools I’ve used is that many rely on binning by month, but that sucks for all the reasons you list and more. I’d love to have a tool that semi-automatically amortizes recurring or otherwise known transactions.
I have a crazy google sheet that takes in a table of raw auto-categorized transactions (from Mint, which I want to drop, but still find it useful for this export even though its auto-categorizations suck) and uses that to re-construct a running history of expenses and net worth. I subset by category to see trends and outliers… it’s rough but I appreciate having the historical view, and that helps me identify categories that are ripe for optimization. I’ve also found it essential to do some sort of smoothing in order to actually see reasonable things behind the high-frequency transactional data — and kinda-sorta do a bit of this amortization — but it’s rough and can obscure things. It’d take some doing to detangle my PII from the sheet to share, but I probably could do it if anyone is super curious.
I’ve wanted to move this into a Julia Dashboards.jl project as a way to experiment with the package and make it easier to iterate on. I’ve also done no attempts at projection within Google Sheets — nor would I want to — but it’s something that’d be much more interesting to tackle within Julia itself.