If you are holding a position, it should be “when will I know that I’m wrong”?
You can answer the question robotically. Good traders never risk more than they can make on a trade. Your risk reward ratio should always be a multiple, but most people tend to take lots of risk while harvesting small profits. Over time, that is a ticket to failure.If you think your trade is worth 100 pips to the upside, don’t risk more than 50 on the downside. You should probably risk less.
Otherwise, you may want to set a price level below which you force yourself to reassess. Has the situation changed? Has sentiment shifted? Has the technical backdrop deteriorated?
The worse thing you can do is fall victim to shutting out incoming information, viewing fresh inputs through the prism of your position rather than from an objective standpoint.
Don’t get dug in. Good trading requires flexibility. It is okay to have a core view, but be willing to take what the market gives you.
Bottom line: Be willing to question your own assumptions and make sure the thought process that got you into the trade remains valid. If not, liquidate and start fresh.