I only use a purse when I need to carry a lot. Usually, that's when I want to bring a drink or snacks. What can I say I like to be prepared on a long day. The bigger the bag I have the more likely I am to carry needless things around all day.
On a normal day I just have a clutch. My phone fits in an outer pocket. In the zipper pocket is my chap stick, military ID, drivers license, credit cards, cash (but that's rare). I wish that I had room for my keys. Those just get stuck in my pocket or I have to carry them.
Now that I'm a nanny I have a bag with a change of clothes tennis shoes (I wear flip flops there) and my bathing suit. I also bring a bag of craft supplies, paper, stickers, ribbon, Popsicle sticks things that are easy to make up something to do.