Should @dimen/* always be used?

Question

Android

Let's say there is a TextView and I specify the layout_width:
android:layout_width="100dp"
Or
android:layout_width="@dimen/text_view_width"
Should I always use @dimen*?

Answer 1

No, you can just specify dp. dimen is mandatory if there must be the same size somewhere in several places, for example.