Anyone who invest on Bitcoin should have a target of when it will sell its bitcoin and also when it will purchase new one, I don't be curious to sell my bitcoin, I only sell my bitcoin when I feel like selling my bitcoin, so we don't have a specific time you can sell off your bitcoin, selling your bitcoin its based on your decision and what you have in mind to sell your coins.
For the aspect of purchasing coins most especially bitcoin, it's obvious and understanding that the appropriate period to purchase bitcoin is when we are in dip, people who have their funds accumulate bitcoin with the period of dip seasons, so it's good to have your funds intact so that you will purchase when the needful arises.
A price "Target" might be good for YOU, but to say that ANYONE who owns Bitcoin "should have a price target" is laughable. You should speak merely and ONLY for yourself, and definitely NOT for everyone else.
If a person truly tried to understand the basics and the technical fundamentals of Bitcoin, then I believe he/she will probably think twice about selling it. It's better to keep it than sell it, in my very humble opinion.

After that, OP said it's only your decision to sell off your coins, in fact - so he may just said it to reinforce the idea.