Short or long: no difference?

Hi. I think a teacher told me something like that when you have a short sentence with an introductory clause (that starts a subordinate conjunction), then a comma need not be used. Would use a comma after the word "jobs." To me the whole sentence is not short but is long. So, would you say whether a sentence is short or long is not important, at least in terms of putting a comma after an introductory clause?

Please note this is a sentence that is made-up to ask a grammar question.

He said when people apply for jobs they tend to think about a lot of things such as pay, a job potential, whether promotions are possible, and a job enviroment.

Also, would you place a comma after the word "conferences"?

Through a series of both pan-Asian and national workshops and conferences (a comma??) much progress has been made in the effort to make ...