At the start of a sentence, we usually add a comma after introductory phrases, such as “on this occasion”, “on numerous occasions”, “on many occasions”, “on occasion”, “on a number of occasions”, “on the occasion of...”, etc.

At the beginning of a sentence, using a comma after short prepositional phrases, like “at times” or “at all times”, is generally optional.

At the beginning of a sentence, add a comma after the expressions in the context of..., within the context of..., etc. to signal that the introductory phrase applies to the sentence as a whole.

At the beginning of a sentence, adding a comma after the prepositional phrases “in the long run”, “in the short run”, “over the long run”, or “over the short run” is often optional.

When using the expressions in the short/medium/long term, over the short/long term, or for the long/short term at the beginning of a sentence, the comma is commonly optional; that is, it can be easily omitted if the sentence is concise or clear.

As a general rule, add a comma after introductory phrases, like “in this instance”, “in every instance”, “in the first instance”, “at the instance of...”, etc.

At the beginning of a sentence, you can optionally add a comma after the phrases “under these circumstances”, “under any circumstances”, “in no circumstances”, “under certain circumstances”, etc.

At the start of a sentence, you can optionally add a comma after a prepositional phrase, such as “in this case”, “in any case”, “in some cases”, “in a large number of cases”, etc.

At the start of a sentence, you can optionally add a comma after a prepositional phrase, such as “in some situations”, “in this situation”, “in a variety of situations”, “in a range of situations”, etc.