DD is nearly 3 yo and we've just started going on playdates. I'm not sure what the "rules" are for playdates, especially when it comes to food. If the playdate starts at 11am, should the host provide lunch? Should the guest bring something? What if it's earlier, should a guest feel obligated to bring something (I always feel like I should)? And in the afternoon, should the guest bring a snack or expect the host to provide something.

How long should it typically last? I don't want to overstay my welcome.

Any other playdate tips would be appreciated. Thanks.