It was his financial bible. The "Blue Book". Securely kept in the secretary desk (drop front) in the living room, it's where my father kept track of the family's finances. With carefully pencil sketched columns for every category of expense and specific items they were saving for, every dollar had a place and was handwritten into the proper location and then re-totaled. He would reconcile the blue book to the actual bank statements when they would arrive and passbook savings ledgers from the bank. That's how I learned personal finance. Basically a spreadsheet without a computer..... because there were no computers.
I tried to manage my own blue book for a while, but by the time I had enough money to even buy my own notebook and pencils, the personal computer was a thing. I figured out that I could create my own ledger system in Lotus 123, and then turbo charge it in Excel a few years later when it came out. I haven't balanced a checkbook since (I honestly don't know where I would find one these days).
So, I had to laugh at my initial reaction being confusion when my son took my beautifully engineered excel spreadsheet and loaded it into Perplexity to do his budget work. What? You don't want to do it MY way? It just didn't make sense. MY way has worked for decades. It's solid, proven if you just follow the process, it's fool proof.... and...... it's old school. What he revealed to me was far more appealing, intuitive, fast and told him a narrative about his finances, not just the numbers. Tomorrow requires different thinking than yesterday.