Hey Lovely..I have 2 bags. A older style huge bag for big trips out. It has lots of compartments, so I can fit nappy stuff in one section, kids change of clothes in an other, my gear goes in the front. We take a seperate cooler food bag. The other bag is a small 2 compartment bag that fits essentials only, I use this for short outings.

I also have a bag in the boot of my car with spare nappies and clothes for all girls

I have always a backpack style bag but I don't think it will fit everything I need.