Define the journey

Start by writing the journey in plain language: user enters the screen, data loads, user takes an action, the app calls a service, the result is shown. Those moments become your candidate signals. If you cannot describe the journey, the instrumentation will be random.

Track decisions, not noise

Good observability is not a log line after every function call. Track decisions that help answer production questions: did the user enter the flow, did data come from cache or network, did retry happen, did the user recover from an error, did the journey complete?

enum CheckoutSignal {
    case screenViewed
    case loadStarted(source: DataSource)
    case loadFailed(reason: String)
    case retryTapped
    case purchaseCompleted
}

Separate product events from debug logs

Analytics, metrics and logs answer different questions. Product events explain behavior. Metrics explain health and scale. Logs explain specific failures. Mixing all three into one vague event makes every dashboard less useful.

Include failure context

When a request fails, capture enough context to investigate without leaking sensitive data. Error category, endpoint name, feature area, retry count, cache state and app version are often more useful than a raw error string.

Review it before launch

Observability should be part of the feature review. Ask: if this breaks for 5 percent of users tomorrow, what will we know? If the answer is not enough, add the signal before shipping.