You can use this phrase to talk about things that sometimes happen. "Every so often" means that something happens again and again, but not very often. For example:
I run into him in the city every so often.
I don't eat sweets all that much, but every so often I'll get a craving for a bowl of ice cream.
The verb that is used with "Every so often" can either be in the present tense, or include "will" like the example above.