Atun - 4:26 pm on Apr 9, 2010 (gmt 0)
Well, I give it the old secondary school try:
How often do you change bids for each keyword?
Weekly -- on average, I'll adjust some, but never all. Changing all bids seems rather rash in the current environment.
How often do you change the creatives for keywords?
Monthly -- I'll be a little bold. Have been rather tentative of late since Adwords has lost the predictabilty of the past.
Quarterly -- Much greater fear of testing during the last couple of years. Fear never being forgiven for a mis-step.
It is a shame, never used to be that way. A/B Split Testing used to be the norm, now I reserve that for other PPC's or the SERPs.