I have an old app that uses reference counting. Should I update it to use ARC?

Yes, you should update your app to use Automatic Reference Counting (ARC). According to the session Analyze heap memory, circumventing ARC is not recommended as it can lead to hard-to-debug memory leaks. ARC provides better memory management and can reduce overhead by allowing more inlining, especially when whole module optimization is enabled. Additionally, manual reference counting can introduce significant profiling hotspots and performance issues.

For more details on reducing reference counting overhead and ensuring efficient memory management, you can refer to the chapter on Reducing reference counting overhead in the session "Analyze heap memory".