![Wink ;)](./images/smilies/icon_e_wink.gif)
If you explore or scan a lot, then the biters bases will over time expand and grow and you'll get in the end a sea of red nests everywhere. The area is basically condemned to expansion, barring massive efforts.
If now you only explore areas where you can, in a not too long time, plop a few structures that will prevent bitters extension, then you'll be in a much better position as time passes.
There is an area of 2 chunks deep, in the dark, that are instanciated and active beyond the explored map, so you need to 'garrison' not too far from this dark border, to be sure no biter arrives from the unknown and plop a base.
my 2 newbie cents anyway... I'll welcome any discussion on the topic of exploration strategy by the way, something that is not that discussed here (at least much less than many topics!)