Adopting a dog is a wonderful feeling for us. Full of excitement and the idea of saving a life. But the experience is not the same for them.
I often see posters stating the 3-3-3 rule. For the first 3 days they are totally overwhelmed but will then start feeling a little calmer. After 3wks they start to feel safer and more at home and then after 3months they have properly settled in.
This idea, at least, makes people realise that moving to a new home is a massive, life changing event for dogs and that they need time to settle in.
However, I find it a little too prescriptive and can set everyoneup for disappointment.