Comma with “sometimes”

In which situations should we add a comma after “sometimes” when it begins a sentence?

With comma

Add a comma after “sometimes” at the beginning of a sentence in these situations:

1. When it introduces a longer or more complex introductory phrase or clause that follows it.
   • Sometimes, when the sun is setting, the sky turns incredible colors.
   • Sometimes, after a long day, all I want is a quiet evening.
2. When it acts as a “sentence adverb” modifying the entire statement, often creating a slight pause or emphasizing the condition. This is often a stylistic choice, but common for clarity or flow.
   • Sometimes, it’s hard to know what to do.
   • Sometimes, I just need a moment to myself.
3. For emphasis or rhetorical effect, to create a deliberate pause.
   • Sometimes, the simplest solutions are the best.

Without comma (normally)

When you can omit the comma (and often do):

• When “sometimes” directly modifies the verb that immediately follows it, and the sentence is short and clear without the pause.
  • Sometimes I go for a walk. (Here, “sometimes” directly tells when you go.)
  • Sometimes she forgets her keys.