Where Caching Helps and Where It Hides Bugs
Caching fixes a specific problem: the same expensive computation or query happening repeatedly for the same result. Applied there, it's close to free performance. Applied broadly, as a default reflex for anything slow, it starts hiding real problems, such as a query that should have an index but instead gets papered over with a cache layer nobody remembers to invalidate correctly.
We apply caching after profiling shows where the repeated work actually is, with an explicit invalidation rule for each cache, so stale data has a defined maximum lifetime instead of an open-ended one.















