I think it is very important to calm down people who are buying Moneros.
I've talked some people about Monero and they all seem to love it and thinking "I need to go all-in XMR".
We as early adopters have the moral responsibility to tell the (legitimate, not NRG's alter egos) newbies not to buy too many Moneros, only the amount they can afford to lose. If someone can afford to lose everything, then I guess all-in is the optimal strategy.
I hope people will listen to my advice.

Yes, it is best to use caution and average your buys in over a longer period of time. Think months, not days. If the price goes down, you get more XMR. If it goes up, then of course you don't have as many XMR if you went all-in, but nobody trades perfectly.
More importantly, if you buy a lot, just ask yourself "am i prepared to hold this indefinitely if the price drops 50% or even more?". If that idea makes you uncomfortable, buy less. You don't even have to believe this will be the outcome, but it is best to mentally prepare for all options.
The option I have difficulty preparing for is the selling part. Holding is easy.