What is the best time for affiliate to change the banner ads?

What is the best time for affiliate to change the banner ads??
Can you suggest how frequently affiliates should replace the banner ads of vendors?

Tricky question. I don’t see a point why you need to change the banner every now and then. I am posting 1 banner per CPA campaign and they are doing well whatever time I post.

Well you want to change the ad before the user becomes blind to the ad, I have a link I bookmarked awhile back regarding Ad blindness http://stason.org/articles/money/passive_income/ads/more_with_less/how_to_prevent_ad_blindness.html

thanks you guys for sharing your experienced tips