We burden mom-and-pop landlords with all kinds of expectations and baggage that we don’t impose on more corporate types. That’s partly because they are, well, moms and pops, with all the psychodrama that those words imply, and partly because they are such a prominent feature of the rental picture here. A 2003 study old, but still the most recent solid data available found that 75 percent of landlords in the city owned fewer than 10 units; 42 percent lived in a building that they rented out. They were also much more likely to manage their own rental properties than landlords nationwide, increasing the potential for friction with their tenants, and they held on to those buildings longer—three decades was not unusual. An estimated 80 percent of rent-controlled properties in San Francisco are mom-and-pop owned.