It's double entry accounting, so when you spend money, you have to give an "account" that you spent from and an "account" that you spent to. For example, if you wanted to track somethings but not others, you can keep your ATM slips. When you withdraw money you simple add a transaction from your "bank account" to your "cash account". Then let's say you wanted to keep track of your spending at restaurants, but didn't care about anything else. In that case you keep your restaurant receipts. You make a transaction from your "cash account" to your "restaurant expense account". At the end of the week, you look at how much money you have left in your pocket. You can enter a transaction saying you have that much left and (with ledger anyway) can tell it to put the difference in your "miscellaneous spending account".

Later your can run a report which shows how much money you spent. It will tell you how much you spent on restaurants and how much you spent on "miscellaneous spending". If you think that you want to explore what you are spending on "miscellaneous", then you can keep receipts for those things and start an account for it.

Remember the point is simply to let you measure things. It's up to you to decide what's important to measure. If you don't think it is important to measure anything, then the accounting package is very accommodating. You just don't use it ;-)

No one gave you a specific analysis oriented answer.

Assuming conditions are mostly static which they are for most people you now have an engineering theory or model with some predictive ability. Capable of answering simple questions about the future.

I'd like to go to the HOPE conference in NYC this weekend. (I can't for familial scheduling reasons but for the sake of the argument...) Given historical entertainment budget how many months ahead do I have to start saving up to pay for transport and hotel? A month? A year? Is is even in the cards for petty cash at all or am I going to have to save up to attend? At our current rate of savings when does my wife get a new car, this year, next year, later?

If you don't have questions like that there's no point gathering the data. Much like I ignore my fitbit and my mint data, I'd ignore this data in general.

Its also an old people filter. 20 years ago you got one checking statement per month mailed to you in physical mail. You'd have a whole month's financial transactions uncleared just hanging out there and then you'd balance your checkbook by whatever method so you could keep a running guess of your current balance. Now a days I have live bank account access and at most only a handful of online payments outstanding at any given moment so I don't keep a paper register or the equivalent anymore. So old people tend to have a "thing" for elaborate home accounting. It took me 30 or so seconds to determine that right now I could write a check for $2356.50 if I wanted to and it would clear, but not a penny more. In the old days it would have required some elaborate accounting OR I'd have to guess I probably have over $2K in checking and hope for the best.

Most likely you would import most of your transactions from your bank, then enter cash transactions by hand, and edit transactions that just show check numbers and wire transfers. Data entry can and should be automated.

Once you have the data in a bookkeeping system (ledger or otherwise), you use it to answer specific questions.

Use it to find out where your money has gone (I spent how much on coffee?!), how much more or less you spent this month vs last, or vs this month last year, how much your liabilities are (debts, like credit cards), how much you've earned but not yet received (from your consulting clients, for example), etc, etc.

Ledger can print out simple text reports, or CSV that you can graph (most people will just paste that into a spreadsheet, but perhaps you prefer gnuplot or whatever).

One thing you can do is reconcile your transactions with the bank's. They are not infallible.

But I'm mostly in your camp. I don't use accounting software for my personal finances. I don't know anyone who does. I think it's more useful for businesses or other organizations that have to be able to report where the money goes.