Reproduce the customer-facing problem
Identify the affected page, device and customer action so the fix is tied to a real storefront symptom instead of a general code cleanup.
Separate theme issues from app issues
Check whether the problem comes from the active theme, a theme customization, an app embed or another storefront integration before changing several systems at once.
Protect revenue-critical flows
Product selection, cart, checkout entry, navigation and key calls to action should be treated as protected customer journeys during theme work.
Prefer small reversible changes
Make the smallest change that resolves the problem, keep a rollback path and avoid broad edits that make later troubleshooting harder.
Verify more than one page type
A fix that works on the homepage may still break product, collection or cart pages, so validation should cover the page types affected by the same theme logic.
Document what changed
Record the symptom, cause, change and verification result so future theme or app updates can be checked against the same issue.