When you place an element on a page, it will always get an id like '#image3' or '#horizontalMenu1'. Now this is perfect, for elements should have an id. These id's are also referenced in site code and page code. In page code, you don't get an issue straight away, but if you make site code, you can get issues. Each id numbering is started again on a new page.
There are situations you will have site code referencing an element. Say you want something to happen to an element on each page. Then you will need to position it every time in sequence for the id's to match. You could place the code in the 'page code' but then you won't be reusing code.
My request is to make it possible to change these id's to something you want to call it. For programmers, not only will you then be able easily reuse element based code, you can then also make the id's meaningful. Personally all my id's have a specific notation which hardly use incremented numbers.