People are usually surprised when they learn of my experience living in 140 square feet. My home, the Mobile Hermitage, is designed for primarily a single occupant, and there are no amenities such as a shower, bathroom, or fully equipped kitchen. So, a more self-sufficient space with included amenities and space for two or more people would, by necessity, require more space.
A small space shared by two platonic friends will, of course, be a different dynamic than two people who are married or otherwise sharing the same bed. An obvious first step for two or more people sharing a small space would be to agree on consuming and using the same products such as shampoo, cleaners, appliances, and other items that can be shared easily. Doing so reduces (in half) the amount of space needed for those things.
One way of dealing with limited space more effectively is to have systems — a place for everything and everything in its place. Small places and small spaces are less forgiving when it comes to clutter. The key to having a system is having everyone know and agree upon the system. Safe Socks is an entertaining short story by Stephanie Reiley about co-habitation.
More information about smaller, simpler, and sustainable living is available at SmallHouseSociety.org
About five years ago, when I assisted Jay Shafer with the design and construction of my tiny home, the Mobile Hermitage, I intentionally designed the home with community in mind. It was because I leveraged my interdependence with the surrounding community and resources that I was able to make the house so tiny.
Community interdependence is the cornerstone and foundation of the movement toward simpler, smaller, and more sustainable living.
Sometimes referred to as New Urbanism, the principle is to have efficiency in the practical overlap and shared utilization of services and resources. An excellent example of this is The Cottage Company and their holistic approach to right sized communities.
The short-lived trend toward bloated and oversized homes was, in fact, a symptom of a pandemic societal illness of isolationsim and selfishness. This is similar to the phenomenon where illness, imbalance, and/or behavioral disorders can lead to obesity. Our homes were becoming obese because of an inability to interact interdependently and cooperatively with each other.