It's called being a human with needs and solving those needs. yes carry a back pack wherever you go. Am empty back pack is light and you won't even notice it. I

It's called being a human with needs and solving those needs. yes carry a back pack wherever you go. Am empty back pack is light and you won't even notice it. I guarantee there are things that you use everyday that you can put in there. Like a user below me suggested, a water bottle is a great first thing to carry with you everywhere. It's not that you might go to the store either. OP explicitly said they do not know when they are going to shop. It is random, therefore either change your behavior to be more predictable or prepare yourself for your known unknown. Excuses like these are childish unless you have accessibility issues.