Moses had 10, I've got 25. After thousands of card transactions, these are the rules I keep coming back to. The ones that have saved me or made me the most money.

1. Thou shalt not buy at peak hype. When the hobby gets excited, prices go up (see: Brunson, Jalen). Wait for the noise to die down, and you'll almost always get a better entry point.

2. Thou shalt stack 2-3 reasons to buy. One reason isn't enough. You need the price chart, the narrative, and the timing all pointing in the same direction.

3. Thou shalt always check pop count before buying. 26,000 PSA 10s puts downward pressure on price. Always know how many exist before you commit.

4. Thou shalt check gem rates before grading. Submitting a card with a 20% gem rate is gambling. Go after cards with a minimum 65% gem rate. It only takes 30 seconds to look it up.

5. Thou shalt buy quality brands. Topps Chrome & Prizm will always keep their value better (and sell faster) than cards from low-quality brands. Those aren’t the only brands worthy of buying, but they’re probably the safest if you’re new.

6. Thou shalt buy 3+ months after release. New set hype inflates everything. Wait it out and find deals after prices flatten out. Don’t be the guy who paid $66 for my 2 base Donruss Mac Jones rookie cards.

7. Thou shalt not submit a card without running the math first. At a minimum, calculate raw, PSA 9, PSA 10, shipping, grading, and eBay selling costs. Compare the upside of a 10 vs the downside of reselling raw (if the card isn’t gradable) or getting a PSA 9.

8. Thou shalt know thine exit price before buying. Decide when you're going to sell before you buy. Not after the card starts dropping.

9. Thou shalt always check past pricing before buying. CardLadder exists for a reason. Know the highs, the lows, and the price where it makes sense to buy.

10. Thou shalt buy liquid cards. Stick to cards people are actually searching for. Potential profit doesn’t matter if the card sits on your desk.

11. Thou shalt buy when it's quiet. Offseason, injuries, slumps, and more. The best times to buy are when fewer people are talking about the player.

12. Thou shalt sell before the absolute peak, not after. You will never time the top perfectly. Selling on the way up is the easiest way to stack wins.

13. Thou shalt not hold a card out of stubbornness. The card doesn't know what you paid for it. If your flip didn’t go as planned, sell.

14. Thou shalt not chase a card that already jumped. If you missed it, you missed it. There are literally millions of unique cards out there. Move on to the next one.

15. Thou shalt put good pics on eBay. Bad photos kill sales. Grab a cheap light box on Amazon or get a scanner (I bought mine for $100 on eBay). That will pay for itself quickly.

16. Thou shalt not renege on an eBay price. If you list it, honor it. Your eBay feedback is worth much more than getting top dollar on a single card.

17. Thou shalt not confuse a good player with a good hobby player. Andy Pages is having an MVP-type season. The hobby still doesn't care. Know the difference.

18. Thou shalt not invest in players with capped upside. If the best-case scenario is "solid starter," pass. The hobby rewards greatness, not competence.

19. Thou shalt stick to sports thou actually knoweth. I bought a Prizm soccer box once. Didn't know a single player I pulled. Never again.

20. Thou shalt not buy unlicensed products. They're harder to sell and hold less value. (Unless it’s a Wemby rookie auto)

21. Thou shalt not break or rip. The math almost never works out. Buy singles. Stay in control of what you're getting. (speaking purely from an investment / ROI perspective. Ripping is super duper fun)

22. Thou shalt not fall for the bidding war. Set your max price before you start bidding. Stick to it no matter what.

23. Thou shalt not buy noisy cards without good reason. Loud hobby chatter around a card usually means the price has already moved. Be skeptical.

24. Thou shalt never count on an award bump. The hobby prices in MVP and championship odds before they happen. You're usually too late.

25. Thou shalt treat every flip as a business decision. Not a hobby decision. Not an emotional decision. Run the numbers and let the math decide.

Those rules have served me well over the years, from a purely profit perspective.

Anything you’d add that’s worked well?