Updating graph efficiency

How expensive is it to update node as “occupied” if any unit is standing on it? Say I want to have nodes with 0.5 radius and if unit moves 1 meter per second, it will trigger node update every second on average. What if I have 50 units like that?
The goal is to have units not considering nodes for pathfinding that are occupied by some other units. Is there a better way to do this?


Updating the actual graph is not very efficient nor recommended.
If you want to do exactly that I would recommend using a ITraversalProvider. See https://arongranberg.com/astar/docs/turnbased.html#ITraversalProvider

Usually agents move too quickly to make it reasonable to take them into account for pathfinding. Often some kind of local avoidance is better suited for that.