we need a brief comma-semicolon refresher. intro clauses beginning with prepositions When, Since, Before, etc. use a comma at the end of the clause. When I was your age, we ate pie. Use a comma to create a compound sentence that uses a linking word like and. sentence sentence, and sentence sentence.

Avoid semicolons at all cost. Use to separate two complete sentences that are related and can be made into a compound sentence without a linking word. I like cheese; my wife likes cheese also. Use a semicolon in a series of items wherein the items are lengthy/complex or themselves contain commas. There was the guy with the goat like haircut; the lady who never walks her dog but loves it more than anything; and the man in the brownish red coon skin hat from PennsylTucky.

The comma can also be used carefully in a rhetorical manner... to mimic speech patterns. there was the thing, and then the thing, oh there was also the thing, the thing, and the thing, and and the thing.

When in doubt use a comma or nothing. Never default to the semicolon.