Affiliates - When do you stop promoting a site?

[cots]

Question. Assuming all is well with a sponsors programme (site live, frequent updates, new affiliate material etc), when, if ever, do you stop promoting a site?

I ask because I see some TGPs/Directories promoting some sites almost daily and yet I have seen no sales on them from '000s of clicks.

OK don't get me wrong I know we all get different levels/types of traffic so there will always be a variance but I am still interested to know.

Last question - how much do you trust "encoded" links via Nats? I recently promoted a new site and the first appearance generated a ton of traffic for them. The next time I promoted the site the traffic was negligible - I am talking clicks in tens/single figures rather than hundreds. Now I know all traffic goes down as each appearance comes along - but sometimes the drop off is incredible.

As an example yesterday I promoted a site using the links given to me in an email "with my code included". Great gallery, great site - clicks 0. Yep 0. Now that ain't right!