A practitioner's checklist for shipping fast apps and a fast build. Measure first, then attack build time, launch time, runtime cost, and make speed a continuous discipline. Synthesized from 12 years of WWDC performance sessions.
Five sequential phases. Measurement first — never optimize without numbers. Then build time (developer feedback loop), launch time (user's first impression), runtime cost (frame rate, memory, network), and finally make performance a discipline rather than a one-time push.
Filter by impact, effort, or scope. Scope tells you which kind of slowdown an item targets — CPU, memory, UI rendering, build, launch, network, or process/practice.
High-impact items that take less than a sprint. Most are config changes, instrument runs, or single-file edits that compound across the whole app.