I started a new playthrough of Breath of the Wild on its sixth birthday and I plan to get 100% this time around. The last time I lost interest at around the 99% mark because there are a few not-so-fun things towards the end, like finding the final Koroks and locations. Upgrading all the gear is also a grind.
In a week's time I finished the four titans and almost 80 shrines, got the Master Sword and completed its first trial. Next up are sidequests, lots of treasure chests and completing the remaining shrines of the base game before I start doing the DLC shrines and titan. I think I played about 30 hours so far, but only found ~10% of the Korok seeds. So overall, I estimate that I am at about 15% completion. But I know from past experience that the completion rate begins to speed up once the majority of shrines and the titans are cleared, so I am expecting about 100 hours of playtime in total.
The biggest challenges are the third trial of the Master Sword and not losing the will to play once I get to the last few percent of the game.
Legend11 correctly predicted that GTA IV will outsell Super Smash Bros. Brawl. I was wrong.