App Store Optimisation gets treated as a pre-launch checklist item: write the title, pick the keywords, upload the screenshots, move on. That gets an app listed. It does not keep it converting, because the two things ASO depends on, keyword competitiveness and creative fatigue, both change continuously.
Store keywords move like search rankings, because they are search rankings
Competitors update their listings, seasonal search terms shift, and the App Store and Play Store algorithms adjust ranking factors on their own schedule. A keyword set that converted well six months ago can be losing visibility right now with no visible symptom except a slow decline in organic installs.
Creative fatigue applies to screenshots too
The same audience sees the same screenshots and preview video every time the listing shows up in search or on a competitor comparison. Conversion rate on the listing itself erodes the same way ad creative fatigues, quietly, and without an obvious single cause to point at.
Treating ASO as a recurring cycle, keyword re-checks, creative refreshes, rating and review response, rather than a launch task is the difference between a store listing that keeps paying for itself and one that needs a fresh round of paid installs to make up for a conversion rate that slipped without anyone noticing.