Here's the breakdown:
Generally, you should use a comma after "instead" at the beginning of a sentence.
* Example: Instead, I decided to go to the park.
Why?
* Introductory phrase: "Instead" functions as an introductory phrase that sets up the main clause of the sentence. A comma helps separate the introductory phrase from the rest of the sentence, making it easier to read.
Exceptions:
* Short and simple sentences: If the sentence is very short and simple, you might omit the comma. But it's usually safer to include it for clarity.
Example: Instead I ran.
* Direct address: If "instead" is part of a direct address, you wouldn't use a comma.
Example: Instead, John, I think we should take a different route.
Let me know if you have any other comma-related questions!