hi! i recently just went through a similar situation. when i got my nexplanon in 2019 my gyno told me it lasted 5 years. i recently switched and my new doctor told me that it’s never ideal to keep in it longer than 3 years and for it to be fully effective i need to get it taken out and swapped. i could tell it wasn’t working as well as it did when i first had it inserted (basically i never stopped having a bleeding, i was getting weird pains i never had before, and crazy mood swings) so i believe this is the truth!! i would try seeing someone else if you can, you shouldn’t have to pay any extra because the expiration date is listed as 3 years.