Oh my goodness. Packing for the boys was an event in and of itself. I knew I wasn't a light packer, but Baxter and Atticus put me to shame. As an adult, I can re-wear certain clothes throughout the trip (like jeans) because I know I won't get them dirty. But with kids, you have to bring an actual outfit for each day and then some.
Here is a little comparison of my suitcase next to the boys'.
Mine is obviously the one on the left (which also included my blow dryer, and all health & beauty needs). The boys' suitcase was just clothes, diapers, dry food/snacks, etc. Our trunk was packed with a stroller, 2 pack 'n plays, a cooler full of baby food, and 2 high chairs. We couldn't have fit anything else into our CRV.
Thank goodness we didn't have to fly. We would have spent a small fortune just bringing everything we did.