What a unit is, and why anybody bothers

A unit is one fixed stake, chosen in advance and expressed in money. Once it is fixed, every bet is described as a multiple of it — one unit, half a unit, two units — and every result is reported the same way. It is a denominator, not a strategy.

Talking in units separates the size of a decision from the size of a wallet. A bet described as '1u' means the same thing to someone whose unit is 5 and someone whose unit is 500, which makes the description portable, and it makes your own history internally comparable because every entry is measured against the same ruler.

Some people define a unit as a percentage of the current bankroll rather than as a fixed sum. That is a legitimate method and it is a different one, because the unit then changes size as the balance moves and past figures are measured in units of different value.

Which is where it goes wrong. A unit that drifts upward after wins and downward after losses is the most common quiet failure. It still gets reported as units, so the record looks like one consistent thing while actually being a mixture, and the mixture always flatters whichever period had the larger unit.

What to do with it. Write your unit down in currency, not as a feeling, and put it somewhere you will see it before placing a bet rather than after.