First chapter, he buys a plastic bottle of water. Right after when getting provisions to leave the city he says he needs a water bag because he doesnt have a bottle of water. 8 chapters later he takes out many empty plastic bottles out of his inventory... really author?
Id keep all those plastic bottles because you know, they are handy. And the glass bottles then? Damn, thats gotta be great to have as well. Yes they are cheap and he can get infinite ones, but still he could find something useful to carry on empty bottles (dragon blood comes to mind).