[dredmorbius]

But higher LEO orbits are pretty stable from what I understand. I'd have to look up data, but we're talking centuries to thousands of years for decay, no?

Geosyncronous is a whole 'nother matter, and yes, anything placed there will probably still be orbiting when the Sun goes supergiant. Ponder that.

[seanflyon]

After some quick searching I could not find any trustworthy numbers on how long satellites stay up in higher LEO. My impression is that it's decades at most, but I could be way off.

[dredmorbius]

Definitely not my area of expertise, but my understanding is that the upper reaches of the atmosphere are quite dynamic, and various circumstances (including possibly solar storms) may cause the atmosphere to reach out further than it normally does. Density of the satellite in question, and extent of any large surfaces (solar panels, etc.) which might tend to increase drag or cause tumbling (a bird does no good if it doesn't point right) are other factors.