What is the need of taking profits overtime? what will you be using the profits to do? those are the questions and projecting 20-30 years will depend on the age of the hodler and if they have also reach their target of accumulation. The only time i can consider to take profits from my investment is after i must have accumulated to my satisfaction and have made a lot of profits which i know that if a take the profits i will invest it on something productive but taking profits and still keep it in Fiats or some stablecoins will make no sense at all so before intending to take profits you should be able to have a concrete plan of what to do with the profits you have gotten from your investments.
Profit is taken either when it's needed or when the target is reached.
Other than that - surely, one should hodl more and stay happy doing so.
Taking profit from your Bitcoin investment Because is needed in other to settle a particular thing is not a good approach, as an investor you are suppose to have a backup funds such as emergency, float and reserved funds this funds are there to help you in time of emergency or when you needed finance for solving an issue, if you have the mindset that when ever you need money you can dip hands into your Bitcoin investment then you are more like a trader and not an investor, as an investor you should be more concern in securing your investment and that is why backup funds is needed.
Your other statement that says one can take profit when his target is reach is a good approach however it depends on the kind of target you set before starting your accumulation journey, if your target is for you to accumulate consistently and hold for 5 or 10 years and you achieved that target is okay to take your profit, if your plan and target is for you to accumulate and hold till you retire from work and you achieved it you can take your profit however from the time your started accumulating till your retirement should be 5 years upward ( just an advice) but if your target is a month or a year target then you are not an investor put a trader.