We bought one about 10-11 years ago when they first came out, and I think they are worth the money. I mean, the thing with OPK's is, is that it is all subjective, YKWIM? Determining whether or not it is a positive is merely trying to figure out if that line is darker than the control, well to me it may look as dark or darker, to you it may. Well they take the guess work out of it, and it tells you when to test, so you are not testing all day everyday. KWIM?? And their resale value is excellent. I bought mine used for $100, and sold it about 5 years ago for about the same. GL!! HTH!