I am looking for some studies that examine how users perceive controls (e.g. navigational icons) that are rearranged based on most recently used. Also it would be interesting to see how rearranging effects user performance. My first thought that rearranging icons could be annoying because users may not know why the icons are moving and cannot remember locations of the icons because they could be different. On the other hand, moving the most recently icons to a more prominent places could make them more easily accessible especially when time matters (e.g. two most frequently icons appear on the first page vs. the second page). Currently I am trying to see if rearranging icons based on most recently used is a good or bad idea for the users.
It is well known that when people select icons or buttons, they aren't consciously evaluating that icon and then choosing it. They are usually going by memory.
The factor that most effects our memory of items to select is their spatial position. So if you move icons as people use them, you will end up subtly frustrating people. As an example, Microsoft Office did something similar years ago, where they would move menu options that you didn't frequently use. This caused a lot of confusion and they eventually abandoned it.
I would suggest looking globally at the most used icons, and then putting them in an order that makes the most sense. But keep the order fixed.
I agree with JohnGB and have also read a while back that users tend to remember the position of icons more so than the icon itself.
There is on instance where I can see rearranging icons by most recent to be of value. If you had a very long list, for example 50 icons, which required you to scroll down the page to see all of them, placing the most recent icons first would be more efficient than forcing the user to scroll down the page.
This would also make sense as once you get past a certain number of icons, the list becomes no longer scannable, and hence having recent icons in the first few positions would make finding the approriate icon quicker for the user.