Usually, American Girl Truly Me outfits and accessories have a lifetime of two years before they retire. I've been an American Girl fan for almost nine years now, and from what I've observed, that's how it works.
The Truly Me line is rumored to get a new meet outfit in Fall 2022, so I decided to look and see what sets are 2 years old or more to see what you should buy if you want them before they retire.
Explore More Travel Outfit
Explore More Luggage Set
Explore the Parks Outfit
Student Council Election Outfit
Be Creative Outfit
Make Some Music Outfit
Let's Sleep Over Pajamas
Yog-Ahh Outfit
Western Chic Outfit
Color Change Highlights Styling Set
Ballet Practice Accessories
Explore the Parks Accessories
Student Council Election Set
Chinese Takeout Set
Spaghetti Dinner Set
Double the Fun Sleepover Set
Don't Forget to Brush Set
Teatime Table and Chairs Set
By the way, this isn't official. This is just my guesses based on what has typically happened with AG releases in my near decade of collecting.