Will a facial fat transfer have truly permanent results?

I have looked at so many providers pages and some say “a few years” or “several years” and some say “permanent”. What are the factors I should be looking out for in terms of technique that would make this truly permanent (extraction, purification, and grafting technique). My budget isn’t huge and I don’t have much body fat so this is really a one shot hope for me. Also, is there usually bleeding with this procedure? Thank you!