esp script assistance required

Hello guys, i am here to show you my esp script. BUT i would like for it to auto update when a color changes ion know how to do that thats the problem

for i,v in pairs (game:GetDescendants()) do
    if v.Name == "Part" then
        if v.Screen.BrickColor == BrickColor.new("Bright blue") or v.Screen.BrickColor == BrickColor.new("Bright red") and not v:FindFirstChild("Esp") then
            Esp.Text = "not green"
            BillBoard:Clone().Parent = v
        else
            Esp.Text = "green"
            BillBoard:Clone().Parent = v
        end
    end
end

esp works perfect when i execute it tells me if its green or not green but, i would like for it to update whenever the brickcolor changes automatically, so the text changes automatically once the brickcolor changes. much help is appreciated for this life crisis emergency.