Quote from Buy1Sell2:
Why
The questions that I ask myself for addressing this issue are
What is my system for position sizing? Is it solely based on my risk tolerance? Is my system essentially around estimating optimal prices (and times?) - for both entry and exit?
If the edge that I have is primarily (or solely) based on predicting price levels, or identifying rules about changing price levels that enables me to enter and exit, then the system could have position sizing rules that can be independent of market conditions and dependent only on risk profiles. In such cases, entry and exit can be in binary levels.
However, if my system takes the market conditions and trade attractiveness into account when determining size of the position (eg - size based on relative win ratio of the trade, anticipated time in the trade, market volatility, changing market exposure at a portfolio level), as the trade develops and market characteristics change, the factor determining the size of position changes, and hence scaling out may be a superior.