The phrase "infrequent events" refers to things that do not happen often or occur rarely.
Sentences with «infrequent events»
Sadly you're going to have to do a considerable amount of zombie killing because levelling up is a strangely infrequent event for such a short game. (wolfsgamingblog.com)
«In all of these cases, infrequent events really drive a lot of decision - making and expenditure or have big economic consequences. (sciencedaily.com)