I am going to italy in July with my husband and my 13 and 15 year olds. We are staying just outside of florence. Should I rent a car to go to pisa and Luca? Do I also go to san gimignano or cinque Terre in the same day
Where are you staying outside of Florence? That will help people be able to give you more accurate help. And no, I don’t think I’d attempt to go to San G and CT on the same day. Too much to see in each one and they are a minimum of 2 1/2 hours apart.
You probably need a car if staying just outside of Florence. And obviously a car is more convenient for the surrounding areas. If you were in Florence you might consider public transit. Parking in all of those areas can be frustrating depending on the amount of traffic.
Whether you need a car depends on exactly where you're staying.
Pisa and Lucca are easily done by train from Florence. Doing so would eliminate any potential parking/ZTL confusion.
No, San G, and the Cinque Terre really can't be done together in a day; they're too far apart. If you meant adding either of these to a Pisa/Lucca trip, that's much too much as well.
Pisa, Lucca and San G in one day is a busy but, but probably manageable trek, if you are focused on what you want to do in each and accept the fact it is a 'quick' peek kind of trip. ( grazing at Costco vs really having a meal)
Pisa, Lucca and CT as a day trip is, pardon the bluntness, sheer lunacy.
Many a time there has been the question posed of 'doing CT from Florence as a day trip' and the consensus has always been its a poor idea. Trying to do CT and 2 other places is a frightful idea.