"Should I get one thorough check done, or set up something recurring?" is a genuinely reasonable question, and the right answer depends less on preference and more on what your app actually does after the check happens.
What a one-time audit is good for
A single, thorough pass, done properly, answers a real and useful question: as of today, with the app exactly as it currently exists, what's actually wrong. For an app that's stable, not shipping major new features regularly, or being checked specifically before a single, defined milestone like a launch or a funding round, a one-time audit answers exactly the question being asked.
Where a one-time audit stops being enough
The moment new features start shipping after that audit, whatever it found is a snapshot of a version of the app that no longer fully exists. A new sharing feature added a month later was never covered by a check done before it existed. For an app under active, ongoing development, a single audit's shelf life is roughly as long as the app stays unchanged, which for most growing products isn't very long at all.
What recurring checks actually add
A recurring check, run on some regular cadence or triggered by meaningful changes, catches issues introduced by new features as they ship, rather than waiting for the next big audit to eventually surface them. It trades the depth of one very thorough pass for consistent coverage over time, which is usually the more relevant trade for an app that keeps changing.
A simple way to decide
- Shipping new features regularly: recurring checks matter more than one deep pass.
- Stable, mostly unchanged, or checking before a specific one-time milestone: a single thorough audit fits the actual question being asked.
- Handling money or sensitive data, regardless of how often you ship: worth both, a real audit at some point and something recurring in between.
Neither approach is universally right. The honest answer is that the choice should follow how often your app actually changes, not which option sounds more thorough on paper.