I will start with the fact that Bitcoin value is different (and imho way bigger) than its price.

Now, to your question. I don't really buy Bitcoin, my accumulation "scheme" is to sell less or more from the coins I earn (from signature campaign or other tasks).
So I sell less, pretty much based on my gut feeling and the needs of my household (for example last week I couldn't save anything, but a couple of weeks ago I've saved the full amount of the signature pay).
Of course, in crypto winter I try to save more.