Well said.

Some advice that I once received: Know the difference between a trade and an investment.

For a trade, you already know your exit (or ladder of exits) before you buy. Once you've bought, enter your exit ladder into the order book. Monitor the trade and adjust depending on changing conditions.

For an investment, hold until the reasons that you bought are no longer valid.

You could certainly sell enough to recoup your initial purchase and let the rest ride. It really depends on your reasons for buying. Was it a trade or an investment? If you can answer that question you'll be on the right track to deciding your exit plan.