I don't really take Trixie or Kasey many places with me-maybe just back and forth from my mom's house. Trixie gets car sick and would much rather stay home and sleep on my bed. I just kind of go by the rule that if I have to wonder, "Is it OK to take them in here with me?" then it's probably better if I just leave them at home.
Plus, my human child really likes running errands with me, so I like to make sure that is time devoted to JUST her.