Buying a stock is one decision. Owning it is dozens of decisions over years, most of them made under the influence of the latest price move. A written process makes those later decisions consistent with the reasons you bought.
A portfolio is a set of theses, each with a size that reflects your confidence and its risk. A review routine checks each thesis against new evidence at fixed intervals, so you act on information rather than on volatility.
What to look at
- Many individual investors hold 10–25 stocks: enough to diversify company risk, few enough to follow properly.
- Size by conviction and risk: larger for durable businesses you understand, smaller for speculative ideas.
- Trim when a position grows so large that one company dominates your results, or when valuation runs far ahead of the business.
- Sell when the thesis breaks, not when the price falls. Those are different events.
- Review quarterly: for each holding, is the thesis intact, has the valuation changed, and is the size still right?
The shape of it
Review = Thesis intact? + Valuation still reasonable? + Size still right?
An example
A holding has doubled and is now 18% of your portfolio. The business is performing as expected, but the valuation now implies growth well above your Base case. Trimming back to 8% keeps the exposure while banking part of the gain.
Where people go wrong
Checking prices daily makes almost everyone trade more and do worse. Separate checking prices from making decisions.
The best routine is the one you will keep. Thirty minutes a quarter with written notes beats daily attention without them.