I have had a mechanical valve for 25 years, since age 12, I sleep with a fan or ac unit in my room so I never hear it when trying to sleep but when I can here it, I am just reminded that my heart is still beating. I will say that eventually, you will forget what its like to not here the clicking. It has become normal to me and I sometimes forget that I even have it. It is easy to say "Just don't worry about it" or "ignore it" but that is easier said than done. I always try and remember that hearing a clicking in my chest is way better than the alternative , had I not had surgery.