So I always have two ads in each group, refining to increase CTR, have driven several over 6%. But instead of editing ads, I always add new ones, because the data (imp, ctr, conv.) resets when I change an ad. The problem is that my new ad starts at 0% ctr, so it takes a while before it starts showing often. What simple thing am I missing? How do I edit a text ad without losing its historical conversion data?
My feeling - and I know it's not universally held - is that the Quality Scores are calculated at keyword level, so the overall performance of the adverts for a given keyword is what matters. If this is the case, then the past clickthrough rate for that keyword is what you should be concerned with, not which advert that came from. So deleting an advert and writing a new one shouldn't make any difference to your Quality Score (until it changes your clickthrough rate).
I'm a little confused, are you looking at creating new adverts in order to assess improvements (split testing) and having a problem with you add not showing immediately because you have your Ad serving option set to Optimise and not Rotate? Changing this setting should allow you to see the results from your new copy quickly. Does this answer your question?