As in, when listing adjectives, for example a 愉快, 安全, and 环保 summer vacation, do you say 愉快, 安全, 和 环保 的 暑假 do you need the he at the end of the list? Is this how you would list adjectives in the first place?
You can use it but it is not necessary.
Unlike English grammar, its elusive Chinese counterpart does not have a rule of prefixing conjunction to the last element of a string of parallel elements. In fact, Chinese tend to utter a really long string of nouns or phrases without using any conjunction, like 我曾经去过英国、法国、德国、意大利、比利时。
But it is now accepted by Chinese people to use the conjunction in an anglicized way, like 我曾经去过英国、法国、德国、意大利和比利时. However, some language purists disprove this usage. My college professor of EN to CN translation concurred with these views and explicitly demanded that we drop 和 when translating.