The Kims' four-bedroom home had one bedroom that never got used—the formal guest room that hosted visitors maybe twice a year. Converting it into a Junior ADU was the fastest, most affordable path to rental income. The 320 sq ft JADU was carved from the existing bedroom plus an adjacent hallway closet, staying within the home's original footprint. A new exterior door provides independent access from the side yard, while an interior door to the main house can be locked from both sides—rental privacy or family connection, depending on the need. The efficiency kitchen fits a two-burner cooktop, apartment-size fridge, microwave, and sink along one wall, with clever cabinet storage above and below. A compact bathroom with corner shower replaced what was a half-bath powder room. The main living space functions as bedroom and living room with a convertible sofa and wall-mounted desk. Total construction time: nine weeks. Total cost: under $85,000. Current tenant: a traveling nurse who needed something small, affordable, and move-in ready. The Kims barely notice she's there—except when the rent hits their account.