The major resources for Computers/Phones/Tablets include: 
  1. CPU (heart/brain of your device)
  2. GPU (graphics and display)
  3. Operatonal Memory (where running apps and program reside)
  4. Storage Memory (system files, your files, paging memory)
  5. Network Connectivity
  
As devices age, battery capacity decreases, but the hardware
generally does not degrade. However, newer versions of the
operating system (OS) and updated apps and programs will
inevitably demand more of the hardware and memory slowing
things down.
Furthermore, neglecting updates, maintenance, poor
housekeeping, and inefficient use of devices will also
diminish user experience. 
If your Mac runs slowly (article applies to most devices)
  https://support.apple.com/guide/mac-help/if-your-mac-runs-slowly-mchlp1731/mac   
Contributing factors can include:
  o the computer/phone/tablet is old and needs to be replaced
  o the computer/phone/tablet is infected  :-o  
  o lack of maintenance and lack of updates
  o internal storage (HD) doesn't have enough free space
  o not enough memory to handle your programs and apps
  o too many programs, apps, processes running simultaneously
  o too much digital cruft/stuff
  o poor internet connection or service
Relevant Resources
  Antivirus 
  Backups 
  Bookmarks And Tabs 
  Browser History And Website Data 
  Connectivity (internet) 
  Desktop 
  Downloads 
  Email 
  Maintenance 
  Messages 
  Music 
  Outages 
  Photos (and Video clips) 
  Podcasts 
  Removing Third Party Apps 
  Updates 
  WiFi Connectivity 
     
     
 
    sam.wormley@icloud.com