There are so many exit strategies so I can't exactly speak on them all as each can be very different. That being said, I can talk about my own exit strategies.
First, let's talk foundational stocks. Since I buy and hold these for the long-term, I don't really have an exit strategy. I hold until such time that there is a fundamental change to the company's business or, if it no longer fits my investment objectives. I have many stocks I've held for more than a decade and which i plan to hold for decades to come.
For growth stocks however, I do have exit strategies. Typically, I look to exit my position and recoup my initial capital. I usually do this at 100-300% gains, depending on the stock. I usually have an idea ahead of time what my threshold is, then i'll book profits by recouping my initial capital and let the rest ride. The rest will ride until such time that I think growth may be slowing, or if once again, there is a fundamental change to the business. I've done this with all my growth positions (LSPD, DND, WELL, DOC, GDNP, GRN, etc).
I still own them all because I still like them, but I also recouped my initial capital on all of them. It will really depend on one's risk profile. Dan for example has a higher risk profile and he typically doesn't book his profits like that. He'll let the full position ride for much longer than I will. Goes back to your investment goals and risk profile.
The important thing is to have a plan and stick tot he plan. Don't let emotions make the decisions for you - that is how investors make mistakes. Becoming a disciplined investor takes practice, but it pays off in the long-run.
Mat