If you are an administrator of your workstation, ClickOnce prerequisites and the package itself are installed permanently, therefore, on the next access, the startup will be almost instantaneous, except if the ClickOnce package was updated in the meantime on the server - in that case, all the files will be downloaded again and reinstalled.

If you are not an administrator of your workstation, you won't be able to install prerequisites.

If you are not an administrator of your workstation, and the prerequisites are already installed, ClickOnce package will be re-downloaded on each access.