There are many ways to express the idea of something happening frequently or regularly. Synonyms for the words "occur often" include "happen frequently," "repeatedly occur," "take place regularly," "frequently arise," and "happen regularly." Other similar phrases that convey the same meaning might include "regularly emerge," "keep happening," "happen repeatedly," and "recur frequently." Additionally, other colloquial phrases such as "come up often," "crop up regularly," and "surface frequently" can also be used to indicate that something happens frequently or regularly. Ultimately, there are many ways to express the idea of something happening often, and choosing the right synonym or phrase will depend on the specific context and tone of the writing.