2026-08-16
Recollection is a poor custodian of capital
In short. This Weltee Journal note explains why an individual should not rely on memory to track assets. It cites Richard H. Thaler, Mental Accounting Matters, Journal of Behavioral Decision Making (1999): mental accounting is the set of cognitive operations households use to organize, evaluate, and keep track of financial activities, and it violates fungibility. It cites Brad M. Barber and Terrance Odean, Trading Is Hazardous to Your Wealth, Journal of Finance (2000): among 66,465 households from 1991 to 1996, those who traded most earned 11.4 percent a year while the market returned 17.9 percent, and the average household turned over 75 percent of its portfolio. It cites IRS Publication 552, which states that a person may forget an expense unless it is recorded when it occurs. The note is for individuals who trade, spend, or hold property from several sources. The next step is to write transactions when they occur and to keep supporting documents with the ledger.
The mind keeps a sloppy set of books
Richard H. Thaler, in Mental Accounting Matters1099-0771(199909)12:3%3C183::AID-BDM318%3E3.0.CO;2-F) (Journal of Behavioral Decision Making, 1999), defines mental accounting as the set of cognitive operations used by individuals and households to organize, evaluate, and keep track of financial activities. The paper's conclusion is not decorative. Each component of that mental system violates fungibility. Money is labelled by its source, its intended use, and the frequency with which one bothers to look.
A household that trusts recollection is already keeping accounts. They are simply bad ones.
Activity without a record is a performance
Brad M. Barber and Terrance Odean, in Trading Is Hazardous to Your Wealth (The Journal of Finance, 2000), studied 66,465 households at a large discount broker from 1991 to 1996. Households that traded most earned 11.4 percent a year. The market returned 17.9 percent. The average household earned 16.4 percent and turned over 75 percent of its common-stock portfolio each year. Overconfidence, they argue, explains the volume.
A person who cannot see the cost of their own activity will repeat it. A written ledger is not a trading system. It is the minimum required to notice that one has been busy to one's own detriment.
The Service is not being poetic
IRS Publication 552, Recordkeeping for Individuals, states the matter without ornament. Good records identify sources of income, keep track of expenses, keep track of the basis of property, prepare a return, and support the items reported on it. The publication is frank: you may forget an expense unless you record it when it occurs. If you cannot produce the documents, you may pay additional tax and penalties.
The same note observes that records are wanted for insurance and for a loan. Memory does not satisfy a lender. Memory does not satisfy an examiner. Memory will not satisfy one's future self on a morning when the figure must be exact.
Write the entry when the fact occurs. Keep the slip. The mind may remain elegant. The books must remain dull.