That is not always true, I have been a long term holder for a long time but I have been checking the daily movements for years as well, there is nothing wrong with checking the price and the movements, it allows me to buy more when it drops a lot, like for example with this recent drop I bought some more, not a lot because I have absolutely no money left, it was literally just 30 dollars, it is nothing compared to what people invest, but that is what I had, and I didn't want to miss this chance.
So, just because you are looking at movements daily, doesn't mean that you are going to make a move, or doesn't mean you are going to sell, it just means that you would like to stay informed with the market you are invested in, that's it.
Well at first don't use yah self to compare others, and I checked your profile and I can see that you have been into Bitcoin for long and am sure you have gotten some good knowledge and understanding about how Bitcoin and the beauty in it . So you are someone that truly understand and have seen the beauty and potential in Bitcoin, checking the market won't be any issues because you have already know that no matter any dip Bitcoin undergo it will surely recover back stronger, so whenever any dip you won't feel your emotions being test but instead you will grab the opportunity to buy more . The reason why I don't still encourage most people to keep on checking Market movement expecially those that are still new into Bitcoin, is because most people can't withstand or bare seeing their Bitcoin stashed decreasing in value whenever there's dip , Thinking that the bitcoin may not bounce back due to the half-size knowledge they possessed at that time which may lead to them making rash decisions that would later affect them negatively (making losses) with thought of cutting losses and I'm once a victim of such .
So as an Bitcoin investor, there's no need to focus more on market movement but rather your Bitcoin accumulation. because is only those that normally trade with their bitcoin for short-term profit that usually spend most of their time in Market. Just imagine one haven't gotten far with his accumulation and he or she are spending of their time in checking Market movement if there's dip or increase in market, wgugh wrong because as the word implied longer-term means that you are holding like 4-10 years. So anything concerning selling shouldn't be such individual aim when he or she haven't gotten themselves some good quantities of bitcoin, so at checking Market movement regularly isn't relevant at all.