Customers hire products to do jobs, not to fit demographics
A 25-year-old millennial buying a minivan is not 'a millennial demographic shift.' They are hiring the minivan to do the job of 'safely transport my kids and sports gear.' A 65-year-old buying a gaming laptop is hiring it to stay sharp and connected, not because they fit a gamer demographic. Jobs-to-be-done (JTBD) flips the analysis: instead of segmenting by age, gender, income, and assuming those predict behavior, ask what job the customer is trying to accomplish and what alternatives they considered. A customer evaluating Slack isn't choosing between Slack and Teams; they're choosing between Slack, Teams, email, group chat, phone, and 'just yell across the office.' Understanding the true competition and the job reveals why they pick your product or don't.
Jobs reveal the functional and emotional drivers of choice
A customer shopping for a car is hiring it for functional transport, but also for status, safety, identity, or family security. Ignoring the emotional job and selling only on fuel efficiency misses the real decision. JTBD interviews (contextual, observational) are harder than demographic research, but they reveal the actual constraints and anxieties driving choice. A mom hiring a stroller isn't just looking for something that holds a baby; she's hiring a product to simplify outings, look respectable in public, and feel like she's a good parent. Products that recognize all three jobs win. Those optimizing only for holding-a-baby lose to competitors who solve the identity problem too.