The script works only for one part but not for the another ones?

I'm currently developing a simulator game and I want to make people spam on the blocks. I have a problem and it is that this script works for one block:

local firstPart = game.Workspace.firstPart
local secondPart = game.Workspace.secondPart
local thirdPart = game.Workspace.thirdPart

local oneClick = 10

game.Players.PlayerAdded:Connect(function(plr)
    local LS = Instance.new("Folder", plr)
    LS.Name = "leaderstats"

    local test = Instance.new("IntValue", LS)
    test.Name = "Test"

    firstPart.ClickDetector.MouseClick:Connect(function()
        test.Value = test.Value + oneClick
    end)

    if test.Value >= 100 then
        secondPart.ClickDetector.MouseClick:Connect(function()
            test.Value = test.Value + oneClick * 5
        end)
    end

    if test.Value >= 500 then
        thirdPart.ClickDetector.MouseClick:Connect(function()
            test.Value = test.Value + oneClick * 25
        end)
    end
end)

I don't know what to do, it doesn't say there's any error but it doesn't work for the second part and the third one. And yes, I have tried several things but they did not work either.