How to change part.Color once a value changes?

game.Players.PlayerAdded:Connect(function(player)
	player.CharacterAdded:Connect(function(char)
		workspace:WaitForChild(player.Name)
		local clone = game.ReplicatedStorage.Cursor:Clone()
		clone.Parent = workspace[player.Name].Head
		clone.Position = workspace[player.Name].Head.Position
		local weld = Instance.new("Weld")
		weld.Parent = clone
		weld.Part0 = clone
		weld.Part1 = workspace[player.Name].Head
		weld.C0 = CFrame.new(0,-3,0)
		while true do
			wait(math.min)
			if reputation == 100 then
				clone.Color = Color3.fromRGB(0,255,0)
			elseif reputation < 75 and reputation > 25 then
				clone.Color = Color3.fromRGB(255,255,0)
			elseif reputation < 25 then
				clone.Color = Color3.fromRGB(255,0,0)
			end
		end
	end)
end)

Basically the script clone a part from Replicated Storage and puts it inside the Head of the player and welds it, after that, it checks if the reputaion of the player is lower then certain numbers, but it won't change the color if the value changes later on in the game.

You can use GetPropertyChangedSignal

--parent a numbervalue called reputation in the local player

game.Players.PlayerAdded:Connect(function(player)
	local reputation = Instance.new("NumberValue",player)
end)

reputation:GetPropertyChangedSignal("Value"):Connect(function()
	wait()
	            if reputation == 100 then
	                clone.Color = Color3.fromRGB(0,255,0)            
		    elseif reputation < 75 and reputation > 25 then
	                clone.Color = Color3.fromRGB(255,255,0)
	            elseif reputation < 25 then
	                clone.Color = Color3.fromRGB(255,0,0)
	            end

end)

When the VALUE gets changed, everything inside the GPCS function will fire.

local value = Instance.new("IntValue")
 
value:GetPropertyChangedSignal("Value"):Connect(function()
print("The value has been changed")
end)

This will detect when the value is changed, so you can do:

local value = Instance.new("IntValue")
local brick = Instance.new("Part")


value:GetPropertyChangedSignal("Value"):Connect(function()
brick.Color = BrickColor3.new(math.Random)
end)

This should work, please mark as solved if this helped!