https://www.scientificamerican.com/article/the-international-space-station-is-doomed-to-die-by-fire/

What goes up must come down—including, sadly enough, the International Space Station.

For precisely 20 years now, the massive orbiting laboratory has constantly been home to humans, the lucky handful of Earthlings who at any given time venture into the topsy-turvy world of microgravity. But like the rest of us, the International Space Station is aging. And it can’t stay in orbit on its own indefinitely—it needs a regular boost or fuel injection from visiting spacecraft. If those boosts stop or something else goes wrong, sooner or later, the lab will fall.