When do we use "rarely, hardly, seldom"?

I'd like to know when should we use "rarely" and "hardly" and "seldom". Can we use these adverbs in the same situation? Or do we need to follow some criteria for using those different adverbs?

"Rarely" and "seldom" are synonymous and interchangeable, used to indicate low frequency.

"Hardly" is not used to indicate infrequency (unless you say "hardly ever," which is synonymous with the other two) but rather the extent of a quality, as it is synonymous with "barely." For example:

The light was hardly visible.

...meaning you could only just see the light, as compared to:

The light was seldom visible.

...meaning you could only see the light sometimes, irrespective of how bright it was.