Show the relationship: "Without Redis, transients hit the database. With Redis, they are stored in memory and never touch the DB. I use transients for any expensive operation with a known TTL — like caching an API response for 1 hour."
Transients: key-value store with optional expiration, stored in the options table by default but upgraded to object cache when a persistent cache backend (Redis, Memcached) is available. Options: permanent key-value store, autoloaded on every request (if autoload is yes), no expiration. Object Cache: per-request in-memory cache by default, but persistent backends make it survive across requests. Use transients for: expensive API calls, complex query results, and data that can be stale for a known period. Use options for: settings and configuration that rarely change. Use object cache for: any data you want cached with automatic invalidation. Strong candidates explain: when persistent object cache is present, transients bypass the database entirely, making them equivalent to the object cache with an expiration wrapper.
Tests caching knowledge in WordPress. Candidates who do not know about transients will repeat expensive operations on every page load. Those who understand the relationship between transients and the object cache can design efficient caching strategies.