Spot the polling-loop smell, implement subscribe/notify/unsubscribe on a class, and trace the lapsed listener leak that makes forgotten detach calls eat memory silently.

`setInterval(check, 100)` lives in every widget on a dashboard, each one asking the counter if it changed and mostly hearing 'no'. Ten widgets, one slow source, thousands of wakeups a minute for a number that ticks once.

Recognize the 'growing switch on type' smell, extract each branch into a swappable algorithm object or lambda, and spot the same shape inside `Array.sort`, Python `sorted(key=…)`, and Java `Comparator`.

A `process(type, amount)` method has gained a fresh `case` every release for six months. Card, PayPal, crypto, gift card, store credit, BNPL, each new payment type adds a branch and pushes the file past 200 lines.

Rotate the multi-method `switch(mode)` matrix into one class per mode, push transition decisions onto the modes themselves, and trace the silent-failure shape where the host re-grows an `instanceof` ladder before delegating.

An audio player's `play()` method starts with `switch (this.mode)`, and so does `pause()`, and so does `lock()`. Four modes today, one `switch` per method, three methods, a fifth mode lands and you're touching every method to add the same branch.

Freeze each button-handler call into an object holding its own `execute` and `undo`, watch the same list of objects become an undo stack or a job queue when you swap the consumer, and spot the shape in Java `Runnable`, Swing `AbstractAction`, Redux actions, and Celery or BullMQ job queues.

An editor's `bold` button calls `doc.applyFormat(...)` directly. Add undo, and every method on `doc` grows a twin, every handler caches the old value, the document class doubles in size, and redo is still ahead.

Pull each `if` from `checkAccess` into a one-method class holding one `next` reference, watch a request walk the chain choosing handle/pass/mutate-pass at every box, and spot the same shape in Express middleware, ASP.NET pipelines, Servlet filters, Python `try/except`, and DOM event bubbling.

Every new role drops a line into `checkAccess`. The function has grown past 40 lines of `if (user.role === '...')`, and every team that adds a role edits the same file.

Collapse N(N-1) peer imports into one central coordinator that holds the rules, watch the same shape inside MVC controllers, MediatR's `_sender.Send`, and `useReducer`'s `dispatch`, and recognize when the hub drifts toward a god object.

An email input calls `submit.disable()` whenever the value changes, add a password field and email grows an `if`; add remember-me and every older handler grows another. Four fields, twelve edges of coupling, and every new one re-edits the rest.