Solo dev writes 74 architecture decision records in 70 days and measures the real payoff

A solo developer working alone for 70 days documented every architectural decision through 74 ADRs, accumulating 18 doctrine rules with no external reviewer or team to justify the effort. The author found that technical memory reliably preserves the fact that a decision was made but consistently loses the reasoning behind it, leading to costly re-evaluation sessions weeks later. By tracking concrete outcomes, the developer estimated saving roughly five hours of re-decision time across 15 instances where consulting an ADR replaced mentally relitigating a past choice. The documentation also helped avoid at least seven fix-then-rollback debugging cycles by enforcing a discipline of forming and testing causal hypotheses before applying fixes. The author concludes that for a solo developer, the return on investment from this practice is personal and self-directed rather than tied to hiring or selling the project.