The closer you get to Earth the shorter the time it takes to come down. So, basically, anything within the lower Earth orbit, it will come down relatively quickly.
Space junk at altitudes below 370 miles can fall back to Earth in a few years. Most debris burns up during atmospheric reentry and vaporizes.
However, stronger pieces made of stainless steel and titanium can survive tremendous heat, once below the dense regions of the atmosphere they literally freefall to the ground.
At a nice altitude like, say, 60,000 feet or so, they’re basically falling vertically and land at a relatively low velocity, about 150 miles an hour, and hit the ground. You can typically hear a shockwave of something like that as they come in.