Thank you @1Email2RuleThemAll for sharing your solutions and for being willing to let others use and modify them. I started building something last night that checks off some of my requirements, and looking at your posts it seems we are treading some of the same ground.
I looked at your solution and you are doing a lot - right now I think I need to solve some problems that are more targeted and so I think it makes sense for me to continue making my own. My household income and expenses this year are unusually varied, so the need is to accurately project current account balance over time through all the flux, to predict high and low points and adjust plans to flatten those out, which is different from a monthly paycheck and burn down, as you have noted.
What I have done so far is modify the Accounts foundation sheet by adding two columns, statement period and due date. Then I created a new sheet called “Credit Due” which figures out for each card a) the current period dates b) the prior period dates. Next I plan to use these to pull appropriate sums from the Transactions sheet for each due date which will affect my current account balance.
I already created a row in the Yearly Budget sheet which pulls the balance from the current account row in the Balances sheet and displays / modifies it over the year based on transaction amounts directly. The next step will be to modify it to use the Credit Due values mentioned above instead of transactions directly.
The next step will be to tag the Categories sheet to show which transaction categories will be paid for by which card. And to project the next 12 months of category spending based on budgeted amounts.
One issue I see with this is that statement periods don’t line up neatly against the Categories budget month periods. I will look at it again later but there seem to be ways around this, e.g. 1) much budgeted spending is averaged and it doesn’t matter where the statement period starts or ends 2) where there are large expenses they can be budgeted based on the expectation of which statement period they will be incurred and/or 3) it seems you can change statement periods on credit cards online or by calling them, so I could just make them match the monthly cycle. I’ll look at that later.
If anyone has any thoughts on the above or suggestions its great to chat about it - thanks!