One of the most beneficial feature of frames is it lets the user to have multiple pages in the same browser.
Using frames we can keep one part of the page static while changing the other parts of the page.
If we create a top frame we can use it as a header i.e, as that page is static it acts like an include page.
Frames can be used to reduce server load, as there is no need to reload all the pages when ever a new page is visited.
Disadvantage of using frames
Its hard to navigate through pages in frames when we have more than two or three frames.
Its difficult to print the content of all frames when compared to a normal web page.
Some old browsers doesn't support frames, so we need to place the content seperately for the people who doesn't have frames using <noframes> ... </noframes>
We cannot bookmark individual pages using browser's Favourites Menu.
Deprecated : FRAME & FRAMESET tags are not supported in HTML5 , better to avoid.
Use <iframe> instead.