Clomid timing

I have been looking through several previous threads to figure out when I need to take clomid, and apparently everyone has there own opinion. I took a little "catch-up" cycle of sust and am now wondering when I need to take my clomid. If anybody knows how much longer after ending my cycle of sust that I need to start my clomid, please let me know.
Thanks alot,
Stiffy

some say 18 days others 3 weeks, if you are worried it is only a 3 day differece. take it earlier if you feel the need to be extra cautious.