Life can sustain itself if there is an energy gradient to be taken advantage of. This includes the possibility of life lasting close to the end of the universe. The point at which it takes more energy to gather resources than you get back is the slow-death line-of-no-return.

Organic life may just be a stepping stone towards metallic/silicon life. In that form life may extend greatly beyond what is possible for organics. Maybe instead of uploading one's mind to another organic body, thereby destroying the host's mind, humanity might transition to a purely robotic existence. I would be fine with that, because our bodies are so easily broken. It would also allow us to go explore the universe without the need to bring the Earth conditions along with us. The most cumbersome, and annoying aspects of a spaceship is usually biological life support. If you had a spaceship of nothing but a propellant system, a guidance system, and the means by which to charge your robotic chassi, that would be a far easier system to maintain in the void of space.