Inactive Tutor answered 04/24/19
I would say that rarely and seldom are interchangeable. "I rarely eat meat," and, "I seldom eat meat," mean pretty much the same thing, and they both indicate how few times it happens. Hardly refers more to something being unimportant. "It is hardly raining out," means it's raining very little. If you want to use hardly in the place of the other two, the correct formation would be "hardly ever," as in, "I hardly ever eat meat."