I invest in a mix of fix-and-flips, rentals held in a few LLCs, and some private lending. Each one needs its books set up differently. Here's the setup that's worked for me, in case it helps anyone juggling more than one strategy.

1. One set of books per LLC. Keep each entity in its own file, with its own bank account and card. Mixing entities in one file is the fastest way to a messy tax season and a weaker liability shield.

2. Track every property separately. In Xero I use tracking categories (classes in QuickBooks), so each rental gets its own P&L. You can see which doors actually make money, not just the portfolio total.

3. Treat each flip as a job. Purchase, closing costs, rehab draws, holding costs and selling costs all get tagged to that project. When it sells, you know your real profit, and rehab costs end up in the property's basis instead of buried in expenses.

4. Lending needs its own schedule. Track every loan by principal, interest received, points and payoff date. Interest income and principal coming back look the same in the bank account, so a separate loan schedule keeps them straight.

5. A monthly 30-minute habit. Reconcile the bank accounts, attach receipts while you still remember what they were, and look at each property's P&L. It beats spending 20 hours hunting receipts in March.

What does everyone else use? Curious who's on Xero, QuickBooks, Stessa or plain spreadsheets, and what's working.