Only 3 inputs. An Excel household account book that shows savings rate and assets 30 years later

I keep a household account book, but I don't know how much money I'll have in how many years if I keep going like this. This ...
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For Those Who Are Always Late with Monthly Reports: 5 Steps to Turn Excel Numbers into a 'Single Page for Decision-Making' | A 15-Year Field Manager's Practical Kit

For those who collect numbers in the field only to be asked by their boss, 'So, what should we do about this?' When the end of the month arrives, you copy the previous month's Excel file, swap the ...