The seventh heuristic is flexibility and efficiency of use. So, accelerators which are unseen by the novice user may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users, allow users to tailor frequent actions wherever possible. Why is this important? Well, while we've said before that recall is problematic for new and infrequent users, it can be very fast for experts who have actually learned how to use the system, who know what they need to do and want to do and are able to do it quickly. Also, different users have different goals. So, you want to allow them to customize their experience to make it more efficient, but it's important not to force them to do so. So, Nielsen talked about accelerators, and accelerators are things like keyboard shortcuts that can make it much more efficient to do common actions like cut, copy and paste. So, in designing a system like a word processor, you want to allow recognition by providing those options in the menu, so users can explore the menu, they can see what the different options are, but also provide expert users with a fast way to do it by learning shortcuts, like command X, command C and command V. By providing users with the capability to add shortcuts and bookmarks, you can make it possible for them to accelerate their own experience. So, for example, most web browsers offer the bookmark capability. So, common pages that you visit, you can bookmark, and of course these bookmarks are going to be different for different people and provides a way to accelerate common actions that you want to take. So, if I wanted to bookmark this page, which is Michigan Online, the University of Michigan's online course listing page, I can add that as a bookmark. Bookmark this page and after that it's going up here on my bookmarks bar and I can easily go back to it, and many other programs offer the functionality or functionality like this to add bookmarks or shortcuts to make common actions faster for users. Another example of how we can make interaction more efficient is to offer personalization, and this is a way to automatically create shortcuts based on user's past behavior that allows them to repeat actions that they're likely to take again in the future. So, for example, if we look at my Amazon homepage or the page that I see when I visit Amazon, we can see that it's been personalized to me by presenting me with options that are either things that I've looked at recently or that are related to things that I've looked at recently, and so it makes my shopping experience more efficient by presenting me with things that are more likely for me to want to look at than forcing me to go through the general search and browsing experience that I might otherwise have to go through. So, while it's important to support new users or infrequent users of a system by prioritizing recognition over recall, it's also important to support expert or repeat users of a system by supporting flexibility of inefficiency of use, which we can do by providing accelerators, allowing for shortcuts and bookmarks and providing personalization where possible.