I think your question cannot be answered well in general terms. For instance, I have pachypodium saundersii. They go mostly dormant in winter, losing all their leaves, but continue photosynthesis thru chlorophyll in the bark/skin. Thus, they are minimally active and need some light and infrequent water. I am told they will die if left all winter with no water. Other pachypodium species need to go completely dry and could be put in a closet.