btdt..30 years. True, but like most things in life, "it depends.." The other side of the coin is that extended "aim" periods result in the Marketing folks (in product development environments) take one of two actions. Either they take what you have and launch a less than ideal product, based on the stereotypical assumption that research will never stop tweaking something, or they cancel the product development due to a lack of progress(or transfer the project to someone else). In my experience they prefer the second route(fire, aim..fire..prior to product commercialization). More is learned well, faster. Extended aims are often largely theoretical. It's hard to sell blue sky hand waving.