Understanding tolerable distress
Structural safety problems that result from foundation movement are clearly intolerable. But beyond that, the correct answer is that there is no one answer that is correct for everyone. Different people have a different tolerance for cracks in wall coverings and sticking doors. It is important in searching for a home to purchase that you be realistic.
Demanding a house that shows no signs of foundation movement, has never shown any sign of foundation movement and never will show damage that could be attributable to foundation movement is not realistic.
You should not buy any home that you are not comfortable with, especially without having a structural engineer make a damage evaluation. But the ultimate decision as to how much damage you are willing to tolerate is one only you can make.