what all should i consider while buying a baby bag/diaper bag?

For me, a diaper bag has to be big enough to hold the following items: - diaper organizer which holds diaper, wet wipes, toiletries and spare clothes - burp cloths - thermal flask - food flask - snacks - milk bottles It also has to be water proof in case if any spillage and easily wearable. For me personally, I prefer bagpacks than slings. Jujube seems like a popular choice with mummies but for me, I chose to just use a regular drawstring bagpack from Cotton On because I'm more of the stuck and load kid