What is the missing word? Death and taxes are both certain. But death isn't +.+.+.+."

Well, I agree that death is not quite certain. I mean, it's unavoidable, but no one actually knows when to say goodbye to their beloved ones. Choosing pet cremation urns made me realize that, and even though it was too late for me to understand the value of life and start cherishing every moment with my friends and family, I'm glad that it even happened.

Death and taxes are both certain but death isn't annual.

https://books.google.com/books?id=0VKJbyTAAjwC&pg=PA&lpg=PA&dq=death+and+taxes+are+both+certain+but+death+isn't&source=bl&ots=ZjiGiS0-Y-&sig=sgKQHX1xinQPgOXQFsj8jJ_ioVk&hl=en&sa=X&ved=0ahUKEwibrK_K4KbKAhUBlx4KHcH8AeQQ6AEIMTAD#v=onepage&q=death%and%taxes%are%both%certain%but%death%isn't&f=false

Death is not certain because nobody knows when he is going to die. some people think that they can live longer if they eat certain kinds of food but this is not true. they can live healthier but not longer.