Track your collection, and keep two pots

Seven columns, one rule, and one uncomfortable number once a year. It is the least exciting habit here and the one I see change behaviour most.

Published 21 Sep 2026 6 min read

The short version

Record seven things per purchase: date, item, source, paid, fees, sold for, net.
If you flip at all, your personal collection and your inventory are two separate pots. Never one pot.
Mixing them means you cannot tell whether the business made money or whether you quietly ate your own collection.
Pure collectors should still track cost. It is not accounting, it is knowing where your money went.
Total it once a year. The first time is uncomfortable. Do it anyway.

This is one part of a longer piece on collecting without going broke. It is the least exciting habit on that list and the one with the biggest effect.

The seven columns

A spreadsheet is enough. There is no app you need to buy. One row per purchase, seven columns:

Date you bought it.
What it is, specific enough to find later. Card name, set code, condition or grade.
Where it came from. Shop, show, group, platform, a person.
Paid. What actually left your account.
Fees. Platform, payment, shipping in, grading if you sent it.
Sold for, when it goes. Blank while you still own it.
Net. Sold minus paid minus fees.

That is the whole thing. The discipline is filling it in on the day, not the sophistication of the sheet.

The two pots

This is the part that actually matters, and it applies the moment you sell a single card for profit.

Your personal collection and your inventory are two different pots. Never one pot. Two tabs, two totals, and a card belongs to exactly one of them at any moment.

People mix them because it feels the same. It is all cards, in the same house, often in the same binder. But the two have opposite purposes. Inventory exists to leave. Your collection exists to stay.

One total across both and you cannot tell whether the business made money or you ate your own collection.

When they are one pot, you cannot tell whether the business made money or whether you quietly ate your own collection to make the numbers look fine. I have watched people discover this the hard way, after two years of thinking they were profitable.

If you move a card from inventory into your collection, record it as a sale from the business to yourself at the price you would have got. Otherwise the business keeps the cost and you keep the card, and the sheet lies to you.

If you are a pure collector

You still track cost. Not the selling columns, just what you paid and when.

This is not accounting nerdery and it is not about profit. It is knowing where your money went. Most people have no idea what they spend on this hobby in a year, and the estimate they would give you if asked is usually lower than the real figure.

The yearly total

Once a year, add up the paid column.

The first time you do this it is uncomfortable. That is the point. That single number lands harder than any rule anyone can give you, because it is yours and it is not an opinion.

You do not have to show it to anyone. You just have to know it. And once you know it, the monthly number from the main guide stops being theoretical.

This section starts at the tracking sheet chapter of the full video.