How Often Are Drops In-Game Cleared?

[Scylax]

I was camping in one spot, mowing down enemies in a survival mission, and had piled up easily 30 life support modules. I didn't want to let them go to waste, so I left them there for a bit until I was really low on life support. I waited long enough though that they all just disappeared at once. How long is the timer that cleans up all items created before a certain point?

[BansheePrime]

There is a limit to how many can spawn at once, after a while, the oldest drops get removed as a new one spawns... can't remember the specific limit.