Not sure, you see the epilator pulls the hair from further below the skin's surface - I won't say by the root because that's a myth - so it will take longer for it to grow back to the surface. However, the hairs you do pull will be at different stages of growth, anagen, catagen etc and will be quicker or slower to grow back. When you shave you just lop the top of and it needs redoing the 3rd day.
You don't have to leave 4 weeks between like you do for waxing and since it's done by you at home I don't see why you can't do it every 3 days as long as there is something there to epilate.
Am I making any sense? I seem to be waffling a bit today