system
Given the following post, respond as if you're commenting on Reddit:
human
How do phones become slower?

I bought a new iPhone XR in December. One thing I noticed really early on was that Snapchat it took pictures instantly upon touching the capture button. Coming from an iPhone 6, this was an sharp contrast to what I was used to. Just the other day I was using Snapchat and realized that there is now easily half a second of delay on photo capture. By this I mean if I move my phone after pressing the button it captures what I moved to - not that it’s just slow to actually show me the image. 

I’m mostly just curious about how this and other delays and hang ups become a prevalent on a once healthy device. I haven’t jailbroken, much as I want to and I’ve got acres of storage space left. I just wonder what causes this?

Side question: Is there somewhere I can view memory usage or is that just naive to ask?
gpt
OS and apps can get less responsive for any number of reasons ranging from shared resources to the new code doing additional work (sometimes computations, sometimes hanging on uploading all your personal info to the cloud).

In the long term, a weaker battery means poorer performance.