Planets on the cusp of the next house

Do you count those in the existing house or in the next house? I know astro.com sometimes puts planets that are very close to the next house in the second one. Is this common practice and in that case, in which situations if not all? Or could you choose which house is more accurate for the individual? Or? How does it work?

Funny. After having posted this thread, I suddenly find loads of info about it on the Interwebby, so all I ask for now is experiences with pushing planets into the next house or anything else you'd like to share about the subject.🙂