As soon as I turned 20, I had partial-incision double-eyelid surgery. It was at a clinic near my home that does both dermatology and plastic surgery, and it was recommended by my older sister's friend. The doctor was not really the type to examine my eyes in great detail; they just said they would do a partial incision, and because I was young, I think I simply followed along. (I regret not looking into more clinics!)
But in less than two years, it loosened a little. So I went back to the same clinic for revision surgery, but that also loosened again two years later T_T. This time I am going to properly get a revision elsewhere. I think the issue with my eyes is that my fat layer is somewhat thick and I have insufficient opening strength, so the crease keeps loosening haha.. So this time, I am looking into an incision procedure plus eye-shape correction!