It it better to make the tool easy to use the first time, or everytime afterwards?
For the newbies, if the use of the tool is not self-evident from the start, you're making their experience difficult. This will cost sales at first. However, if you design the tool to be incredibly efficient to use once you've figured it out, the people who've pushed through the learning curve will stick with you longer.
It all depends if you target mostly one-time buyers, or focus on long-term business relationships.