from what I have heard, kmart will offer layby until close to xmas, but their everyday low price sale will go until christmas. I would think it is because so many swore off them after the last 2 or 3yrs with the consistent xmas layby stuff ups.
We dont use it, mainly because they always have way better sales closer to xmas, but also our girls interests change fair bit in 5months Thats unless we layby a trampoline or something big