Facebook changes very fast (true for most other social platforms as well).
If you don’t keep up with the pace of the change, you’ll have loose ends hanging on your Pag
e. Over time, these will diminish the value of your Page and make it less attractive to the fans. Whenever there is a change in design, layout, content or features, make sure you transition fast and transition completely.
Otherwise, you’d be left wondering, ‘Who moved my Like button??’ :-p