I'm a long time green card holder, but never became a citizen. I moved out of the US five years ago, returning twice for quick visits in the first year. Since then I haven't been back, and I realise that I probably wouldn't be able to get back in even if I wanted. Now my question is should I bother to file the I-407 and return my greencard, or should I just let sleeping dogs lie and let it expire next year? Are there any advantages to one or the other? Thanks for any advice anyone can offer!