Hey mommas. What do you do with carseats if you use multiple vehicles?

Right now his carseat is in my car-- he is now on one of them "forever carseat" things. My hubby and I both work. I would like them to be able to go anywhere they need to while I'm at work but I dread the idea of transferring carseats every single time.

I'm afraid one of us goes somewhere and forgets to leave the carseat then the other one is stuck.

Do you guys have 2 carseats? Any recommendations?