When visiting the city from the suburbs, I'll often spend most of the day there, shopping, eating and engaging in similar fun activities.
I'll usually take a backpack in which might have water in it, a book, portable phone charger, etc.
Over the course of the day, I'll generally get tired of carrying the bag, as well as perhaps a jacket, and the shopping bags I've accumulated.
What are some life hacks I could use to store and keep my bags safe while in the city?
Ideally these would be free - or relatively cheap.
One I've thought of is being a member of a gym, and utilising the usually free lockers at the gym for a short period. This might work; in my case I'm already a member of a gym that doesn't have an outlet in the city.
I'm in Melbourne, Australia, but feel free to answer in a sufficiently broader way that could work for any city. I'd be interested in universal ideas that could be applied in any city with a bit of further research, as I'd probably want to do this when on holiday too!