While using VNC I open up port 5900 which I assume is the default port for VNC (I made no changes) and of course now my router has a hole in it when VNC is running...

I use a strong password for VNC so am I safe to leave the port open at all times or is it better to close it when I don't need it? Will leaving the port open allow anyone in?

Thanks for any clues you can give me