I have 2 local scripts in the StarterGui at the moment that are both initially disabled.One of them places a room, and the other places a single block. When you click on a button, it changes the script to enabled and allows the user to place the room. Here is the code inside the button that activates the placement script:
placement = script.Parent.Parent.Parent.StorageRoomPlacement
script.Parent.MouseButton1Click:connect(function()
placement.Disabled = false
end)
However whenever I start the game, it outputs an error that says: "20:55:49.221 - StorageRoomPlacement is not a valid member of PlayerGui", and now the other script says the same thing. Are you only allowed a certain amount of local scripts in the StarterGui or is it something else?

3 comments
There is no limit on how many scripts you can have in StarterGui.
I don't think ROBLOX sets a cap, but too many will affect game performance. Your error means that the path is incorrect. It may not have loaded yet(use WaitForChild()) or you may have moved it or its just pointing to the wrong location
It will lag your game if you make the scripts laggy but there is no limit