How To Thrive (Not Just Survive) in a Small Apartment

When we first visited illustrator Lisa Vanin's Toronto studio apartment a couple of years ago, I was so impressed by how she made 390 square feet so livable. Cozy colors, vintage finds, a distinct living room and bedroom area--Lisa's clearly a small home arranging wizard. But can living in such a small space be sustainable -- mentally or physically -- for the long haul? Can one thrive in under 400 square feet for years and years?