I think anyone who is accumulating bitcoin for the long term should not concentrate more on the pumping of bitcoin, because you will be holding your bitcoin for at least 4–5 years. Your main focus should be on how you will consistently accumulate the quantity of bitcoin you want to hold within the time you set aside and also hold it until the year you want to sell it.
This is just the summary of the whole thing. Instead of the back and forth argument of which buying method is best and which is not, just accumulate Bitcoin, save it properly and give it time to grow. No one will care if you bought all your Bitcoin once or if you bought it in several stages, as long as you have a good stash of Bitcoin which you collected and preserved for the long run.
What I have come to understand is that when the investor have a target in terms of quantity of Bitcoin he is working towards having, it will better influence his buying pattern and how aggressive he will become. For instance, an investor who set target of 2BTC in five years mostly be more aggressive than another investor who have no target. I think setting targets in terms of the quantity of Bitcoin to achieve, should be highly encouraged.