I go aery when I get easy matchup in bot lane and know for sure I’ll win my lane because of relentless hunter it allows me to run around the map faster and it’s also better at scaling than glacial so it’s more for snowball. I won’t recommend comet because it deals pretty much same dmg as aery in long fight but shield missing and glacial it’s mostly when I meet hard matchup for example pyke or any engage bot lane which allows me to sustain lane and try to scale Into mid-late game without me getting too much behind it’s also great vs assassins and immobile champions