Before the 3.3 update it was hard to find this stuff, too hard. I would spend days looking, flying or driving across some tiny moon or another looking for some unusual signal. I spent most of the first three months of 2016 looking for barnacles, eventually finding one only to discover that not only was it not a new discovery but it had been farmed out, presumably because it was one that was particularly easy to find.
Later I looked in untagged systems, working my way around the galaxy in a ship equipped to survive any encounter and found a few (about a dozen) geological sites, never more than one per small moon. There was always more to find, I never found any biological sites, I found a Guardian site near the core but again it was well known presumably because it was easy to find, and later still, just before the 3.3 update I went specifically looking for Guardian sites (the ones with the hostile skimmer-things) using the civilisation filter on the galaxy map and found a few (they were signposted in the system so once in the system it was pretty easy. I never used external help other than knowing that a particular thing (eg barnacles) existed in the game.
During the 3.3 beta I used the new mapping functionality on a moon in my home system I regularly visited for mats & missions, and identified fourty-odd geological POIs (I had never found a single one there before). I took a screengrab of the co-ordinates and visited one of the sites in the live game, sure enough it was there too, it had always been there.
The 3.3 update has made it much, much easier to find what is there, arguably too easy. By the end of December I had seen more persistent surface POIs than I imagined possible without the probes telling me where they were, what was once a rare treasure became mundane, good only for farming mats. I found far more in space that was new and (I presume) added in 3.3, ticking a few more codex boxes, and visiting different regions kept me going 'till around the end of January and by then I felt I'd consumed enough of the new content.
In one update to the game the enormity of the galaxy was reduced to ticking boxes in one region, then moving on to another region. I visited 5-6 regions & feel no great urge to repeat the same simple search in the others so I returned to the bubble.
But I play most days, for several hours at a time. For most players it is more than enough, but for me the scope now just feels so small. Not because of how much there is to find or the variety, but because what there is is now so easy to find.