One of my friends lived in a squat in Melbourne for a few years. They sort of ran it, meaning they would put the place on couchsurfing.com to attract more people. They had anywhere between about 4-20 people living in the house at any time, each staying anywhere from a few days to a few months. The place was a little bit run down, and had no electricity or running water, although they did have gas and were able to cook food. They used candles to light the place at night, and would retrieve water from a nearby public tap and shower at a nearby university. They'd also dumpster dive all their food. The place was actually pretty awesome and had a really great community feel, albeit run-down and mouse-infested. There was lots of artwork and poetry printed directly on the walls.

They'd often have lots of people over and spontaneous parties were common, though they had to keep the noise down since the owner could theoretically come at any point and kick them all out, and in the end that's exactly what happened. The owner was actually pretty nice about it, and was impressed at what they'd done with the place, but kindly asked them to leave, which they obliged. The house is actually still there and my friend hasn't lived there for years so I'm not sure why the owner kicked them all out.

On another note, Moxie (of Signal/Open Whisper Systems fame) has some pretty cool stories about his adventures in squatting - https://moxie.org/stories/together-two/