The atmosphere is still thick enough to drag you down at 500km. You would last typically last a few years before burning up - the rate of fall is pretty low at 500km. But you do need fuel to do collision avoidance manoeuvres and for attitude control (otherwise your panels will no longer face the Sun and your antennas will not face the ground).

Thank you, I think it might have been collision avoidance and/or attitude control that I was thinking of then, rather than actually burning up. I remember reading about this in relation to the ISS which needs frequent adjustments, although is a bit lower than 500km.

Quite helpful infographics from ULA: https://blog.ulalaunch.com/hubfs/orbital%20debris.jpeg

Jonathan McDowell keeps track of all the Starlink Sat orbits, including failures:

https://planet4589.org/space/con/star/stats.html