Nitty gritty nit repellant - does it work?

[madcows]

Hi all,
Title says it all. Does anyone find that this works?
Having cleared my ds a couple of weeks ago, I checked him last night and found 3 adults (but no eggs). Just done another check and found one more adult, but again no eggs.
Y'day he spent some time with the friend who we think he got them from last time, so maybe they jumped across y'day (or maybe we missed a few...)
As a result I've bought some of the repellant, but am wondering if this is (rather pricey!) wishful thinking.
Anyone any experience of it? (good and bad!)
tahnks,
madcows

Seems to work well, I use it on my dd. Stopped using it for a while and she got nits, so we are back to using every day now.