The US Space Surveillance Network has been tracking over 22,000 pieces of debris larger than four inches. Most reside in low Earth orbit, approximately 600 miles above the planet’s surface.
In the vacuum of space, objects can stay for over 100 years because there’s no air resistance.
But they will eventually undergo orbital decay and lose energy, because even at these altitudes there’s a very slight atmospheric drag, as a result, the Earth’s gravity will eventually tug them back down into its atmosphere.