title: Store row count in database or get dynamically
body: <p>Say I have a table full of comments, each from different users, and I want to count how many comments each user has. Should I have a separate table with the count, and update that on creation/deletion of comments, or should I query the count every time?</p>
  
  <p>I feel like the latter is better, but I want some more experienced input on the matter. Thanks.</p>