Selling and taking profit during the bull run is not ideal because after selling, you might not be able to buy back at the price that you bought before and this will make you have less bitcoin that the initial amount that you had before selling. Meaning that you don't have a bitcoin target and you are not focus on accumulating bitcoin on a long term investment. Another reason why this strategy is not the best is that you will miss out the compounding interest that your bitcoin investment will accumulate for you if you only keep on accumulating till 10yrs time or more. Try and see your bitcoin investment as your life savings and not for profit alone because nobody knows if at the long run it is your bitcoin investment will be the one to take your to the next level in future because there is high possibility that bitcoin price might keep on increasing with timeline. It is better to save for the future than saving to sell and take profit and buy back again. All bitcoin sold can not be bought back easily because of the change in price towards the upside. It is also a bad idea to sell all your bitcoin investment and hold fiat. What is things didn't work out as you planned it after selling, that is when you will regret your action.
I don't agree to your assertion that it's not ideal to take off profits within the bull run like what's the essence of investing? Isn't it to make profits? So in a situation whereby an investor have achieved his major aim of investing which is to make profits so after selling off his bitcoins the next for him to do is to pause investing for sometime until the price begins to dip then he can start buying and holdling again till he aquires a reasonable amount or better still he apply the DCA till the price skyrockets again so that's what an experienced investor does.
You are not to sell all your bitcoin because you want to take profit and fill that you have arrived. Instead, you should sell part of it, if you have reached your bitcoin target so that you can diversify into another investment like property, stock, bond. Why do you stress yourself to accumulate for a long period of time just because you want to sell all your investment. What if after selling all and you are holding fiat and the price of bitcoin didn't dip to the price that you expected ot means that you will only buy little amount of bitcoin and you should not forget that they more you are waiting for bitcoin price to dip, your fiat currency is depreciating. Why do you want to start from the scratch again by starting as a newbie that just started his bitcoin journey. It means that you didn't realize the potential of bitcoin during your period of accumulation and the compound interest is what makes it more of a better investment than any other investment.
How long do you think that it will take you to build up your new butcoin portfolio that you just started, it might take even double of the years that you used to build the first one because one thing I guess that you have not considered is that for every circle bitcoin dip price is always higher than the new circle and the amount that you used to buy lets say 0.003btc in the first circle will be higher than the amount that you will use to buy 0,003btc in the second circle. There is what id called a maintenance stage as explained by JJG, if you have reached your bitcoin target, you can start maintaining your bitcoin investmnet by limiting buying regularly and buy once a while either by lump sum or you buy at the dip. Umagine that you accumulate 1btc for 10yrs based on your regular DCA approach and you sold off all of it after ten years because you feel that you have reached your bitcoin target, and you fo back to square one and start accumulating again to reach 1btc again. It means that your bitcoin portfolio is not increasing more than one level and wouldn't get tired of accumulating over and over again, mate I must tell you that a time will cime that you will never be able to continue with your accumulation because we don't know some unforeseen challenges that we befall on you and you will also be getting old and this shows that you will never reach that fuck you status that you don't need to work for anyone again but only depending on your bitcoin investment to take care of you in your entire life.
investments should be there for as long as we are leaving so that when we are old and can no longer work, our investment will take care of us and out children. A successful investor don't start deom the scratch if not you will never be successful. If you have reaced your bitcoin target, you can sell like 20% of it and keep 80%, so that as time passes by your compounding profit will also be increasing, than you starting all over again like a newbie. This means that you have nothing to show that you are an OG investor in bitcoin and you will gave little profit like all those beginners.
In trading, making profits is not guaranteed all the time so accumulating for a very long period like 10 years as you stated may not really be an obtainable idea as the future is unpredictable no one knows how the fate of the coin might turn out due to some uncertainty that surrounds the stock market. Making accumulation for a very long period of time might even lead to losses because in the quest of hoping that the price will skyrocket then it suddenly starts dipping so it's really not ideal to accumulate for too long as no one can speculate or predict what it's future holds.
This is where you got it wrong because bitcoin is not stock, so you don't use the stock market to judge bitcoin. There is a high probability that bitcoin fiture will be brighter than been dull. It is because no one can predict the future that should also make you not think that selling all your bitcoin and start all over again to invest is the best instead of keep on hodli and maintaining your bitcoin portfolio by buying once in a while and diversify to other investment. Growth is what matters alot and not the opposite.