Either that or use literally thousands of unique stamps, so that the odds of a single explorer "being struck by lightning twice" go down considerable. Does anyone have any idea of how many unique terrain stamps / prefabs Frontier is using? Is it hundreds, or just a dozen?
The problem here is the "birthday paradox".
If you can see, say, 25 regions from a decent "high orbit" position (which seems to fit with the sizes of repeats people point out) ... then there needs to be over 625 large-scale terrain stamps for someone to have a mere 50:50 chance of not seeing any duplicates. On any one planet.
If you then want to get it down to the odds where someone won't see duplicates if given a random selection of 20-50 planetary views
and also have different sets of terrain for rocky, icy, low-G, high-G, etc. it requires having millions of distinct terrain stamps (maybe rather more than millions; the calculation is more than I have time for right now)
(The distinctiveness does make it trickier, also - the rock scatter in Odyssey is
way more varied and interesting than in Horizons, but everyone always remembers seeing Sandwich Rock before. But apart from that it is way more interesting than in Horizons for different sorts of rocks, rock density matching up to the landscape, rocks looking like avalanche results, etc.)