Hardly & barely

Hardly, barely and SCARCELY are interchangeable (Fowlers). Hardly, in dialect, appears in at least three erroneous forms: can't hardly (for can hardly), not hardly (for hardly), and without hardly (for almost without).

.... so would it be correct to use "hardly" and "barely" interchangeably in this kind of sentence?
"She's hardly ever/barely ever at home"

...and which one is correct?
"I can hardly wait" or "I can barely wait"

Regards.

I think that’s a matter of usage isn’t it? I’m hardly ever at home. I’m barely there. I guess they are different aren’t they. But how would you define the difference? It seems to be a matter of idiom more than an issue of grammar.

What about scarcely? She is scarcely at home when he is there.

Oh... yes, I have to say that they're not totally mix 'n match. But pretty close. I wonder how I might define the difference between the words without simply citing the dictionary definition of each individual word. I assumed that the task was really about finding relationships and defining classes. All three words are in the same class and perform the same function (within reasonable limits). Wh

She is rarely at home.

I scarcely know him.

She'll be at home all day. Maybe she'll go for a walk. Could you use one of the adverbs here?