Household Digital Subscription Avoidance: A 10-Year Backtest of Avoidable Recurring Spend vs Self-Hosting

Multi-year comparisons of self-hosting versus cloud subscriptions rarely account for manifest-sourced price histories, storage-tier jumps, hardware replacement, and explicit rules for licensed media. We backtested nine synthetic Brazilian household configurations across 2015–2023 entry years using 103 subscription observations, 718 self-hosted cost rows, and a 540-cell deterministic grid (four media scenarios, IPCA-deflated real prices). Under conservative media (streaming not counted as avoidable), focal entry 2021 with a 5-year horizon yields positive net savings only for storage-heavy personas: P2 Google/Apple (+R$348 to +R$541), P3 Google (+R$1,170), and P4 (+R$4,975); P1 and streaming-only P5 never reach payback. Identical NVR hardware produces opposite P3 outcomes when camera cloud is itemized (Google) versus bundled in iCloud+ (Apple); a ±20% hardware capex perturbation flips P2 Google focal net from +R$918 to−R$222, joint hardware–energy stress (+20%/+20%) turns the same cell negative, and literature-interval media-fraction bounds span ≈R$1,800 on P5_hybrid focal net. Practitioners should model multi-service baskets and tier jumps, not per-gigabyte list prices alone; labor, reliability, and privacy sit outside the cash-flow model.