Locator strategies in Appium for mobile elements — which do you know, which have you used, pros/cons?

In Appium, different locator strategies are used to find mobile elements:

• id — search by the element's unique identifier. Very fast and reliable if the id is stable.
• accessibility id — search by accessibility label (e.g., content-desc in Android or accessibilityIdentifier in iOS). Good for testing, as these attributes are often used for accessibility.
• class name — search by the UI element's class name. Fast, but may return many elements if the class is common.
• xpath — search by XPath expression. Very flexible, allows searching through complex structures, but slow and fragile when UI changes.
• android uiautomator — specific to Android, allows using the UIAutomator API for searching.
• ios predicate string and ios class chain — specific to iOS, allow searching elements by predicates or class chains.

Pros and cons:

• id/accessibility id — fast and reliable, but require developers to set them correctly.
• class name — fast but may not be unique.
• xpath — universal but slow and fragile when interface changes.
• android uiautomator/ios predicate — powerful but require knowledge of specific syntaxes and can be more complex to maintain.

In practice, I most often use accessibility id and id, as they provide a good balance of speed and stability. I use XPath only when other locators are not suitable.