How long until dermal anchors fall out?

I had my dermal for 2 1/2 years. I always took care of it and it kept getting red. Finally after the first year it calmed down. Then about 15 months goes by and it swells. I get it taken care of and then 6 weeks after that I woke up and it was sticking out. When I went to place it back in, it simply fell out. They don't always last forever.