For stays 5 days or longer, allow 1 dog above capacity if it's only for 30% or less of the stay, What does this mean ?

This means that if, for example, you have given yourself a limit of hosting 1 dog at a time and you get another request for a long-term sit, Rover will allow them to overlap a little.

This prevents you from overbooking yourself (and accidentally misrepresenting yourself to clients) but also keeps you from missing out on potential long sitting gigs.

Hope that helps!