How to check is an object is a certain distance away from my character?

I’m writing a script that launches an object far away from the player’s character and after it’s out of range, it despawns. How do I check whether the object’s out of range of the player?
I tried

 local Distance2 = (HumanoidRootPart.Position - Mjolnir.Position).Magnitude
		if Distance2 > 15 then

to calculate the distance and destroy the object but it doesn’t work, what did I do wrongly?

Debris:AddItem will remove after ten seconds if you don’t specify. Why not just Mjolnir:Destroy()?

Is this section of script inside a loop?
If it isn’t it only checks once, then continues.

It checks everytime the remoteevent is triggered.

I read somewhere that there is a slight delay with destroy(), whereas Debris:AddItem() is instantaneous or something.

I switched to Destroy() and nothing changed, so the issue clearly lies with the distance checking.