how do i check if a variable has changed?

So Im trying to make it so that when a variable changes

it fires something

for instance

Var = 0



--if it changes do something here

For Values

script.Parent.Value.Changed:Connect(function(changed)
--Do whatever
end)

or

For Variables

while true do
	wait()
	if variable == true then
		--Do whatever
		return
	end
end

With physical values, do this:

local Value = script.Parent
Value.Changed:Connect(function()
	--Thing here
end

You could use a print statement and the GetPropertyChangedSignal event.