Well, I do a bunch of apricorn, dream ball, and "special" ball breeding and less than half my stock of females in non-standard pokeballs has the desired nature. So, when I start a new species or a new ball for a species I've done before, I have to grab a good enough male with that nature to breed with the female until I get a female I can then breed with the ditto.
I mean, I could breed without an everstone to start with until I get a female with the correct ability and nature, but it's actually quicker to just everstone breed her with a same-egg-group male instead.