A long term bitcoin investor only need to be able to figure out his or her discretionary income to use and accumulate bitcoin and hold for the long term goal. I don’t really understand what you have in mind when you are talking about observing when to buy, but if it is all about you trying to observe market price before you buy or accumulate bitcoin then you’re getting a wrong investment mindset and that is a mindset of traders who only comes in for a short and quick profit making mindset. They waste time trying to time and observe the market to buy whenever they noticed the price is low so that they can sell when the price is high, and also they panic and sell too Early whenever they noticed a little downturn in the market price or when it’s not going their way and that will lead them to a loss because at that time they will surely sell at a huge loss.
As a long term bitcoin investor, you don’t have to observe the market price before accumulating bitcoin, all you need to do is to focus on figuring out a discretionary income to consistently or perhaps persistently accumulate bitcoin and hold for the long term purpose, using the DCA method of accumulation either weekly or monthly depending on how your income flows.