Personal finance isn't just about building up net worth—it's also about making money available when you need it.  Just like a business, you have to worry about your balance sheet and your cashflow statement.  Having a lot of money locked up in investments isn't helpful when you need cash to cover expenses today.

This is the logic behind the emergency fund—hold a couple months' expenses in fairly liquid form, like a savings account or US Treasury I Bonds, to smooth over unexpected changes in expenses and income.  Establishing an emergency fund should be your first act before considering any other kind of investing.

How much money should you keep in an accessible place?  To make that decision, you have to balance two opposing forces: the risk and cost of having too little, and the cost of not investing in something with a better return.

It's been almost exactly two years since I waxed poetically about Mint (mint.com) for expense tracking.  Mint connects to your credit card, bank, and investment accounts and automatically pulls in and—with decent accuracy—categorizes your transactions.  I still use Mint on a weekly basis and recommend it without reservation.

---

Expense Aggregation with Mint is Awesome

The Mint team has also added billpay, a free credit score, and budgeting tools, but the transaction aggregation is the killer application for me.  With a glance at the site or the Mint app (Android, iOS), I can check the cash in my checking account and verify it covers the total charges sitting on my credit cards.  I can skim my recent transactions for unexpected fees, errors, and easy-to-forget repeating subscription charges.  I can even download my entire transaction history, all the way back to January 2012 when I started using Mint, as a .csv file for further analysis in a spreadsheet or Python script.

---

Travel Back In Time

Mint keeps track of your account balances on the last day of each month and this data is also exportable as a .csv file, so it's easy to look back in time and generate a net worth graph:
Mint usage automatically makes you more aware of what's happening with your money, and this increased awareness inspired a reformation of my spending habits... and the transformation of this site into a full-fledged finance blog. 

---

OneReceipt Makes Mint Even Better

The one piece of information that Mint doesn't capture is what you actually bought in a given transaction.  This is sufficiently annoying to me that I anticipated it would annoy enough other people to rapidly precipitate a solution, so I've been sealing each month's receipts in a plastic bag and tossing them in a shoe box under my desk.

All of my receipts.  Since August 2011.

FINALLY, a startup called OneReceipt has solved this problem.  According to the timeline on the bottom of their homepage, they too have been thinking about this since 2005.

∴ I am not crazy.

OneReceipt roots through your inbox and scrapes electronic receipts, and their iOS app takes photos of paper receipts and uploads them to a server for optical character recognition (OCR) and processing.

Turn THIS...




































...into THIS



It got all of the items right!  It sees discounts and tax!  It can even get the timestamp!

It gets better.  Install the OneReceipt Chrome Extension, fire up Mint, and:




And of course, since this is obviously my early birthday present, you can export all of your receipt information as a .pdf or .csv.

Oh hell yes.

Thanks OneReceipt!

Follow the team on Twitter or Facebook or Google+ or whatever.