When we adopted Flower she was tiny, about the size of an adult teddy bear hamster and she hasn't grown much at all. She's still a dainty little girl but we wanted to give her more room to run around. So Ken decided to wire together two cages and give her twice as much room. We already had both cages.
So Ken cute some of the wires off the top of the cage to make a hole for her to get to the second story and used a metal file to file the edges so they wouldn't cut her.
Then he wired both top and bottom together and she started exploring immediately.
I think she approves.