In PrE and PrPro, when there are no Handles, the Clips will have a little "triangle" in the upper portion of the Clip, at the Head, or Tail. This shows those triangles in PrE, and PrPro is about the same:
Now, if there are no triangles, that only means that there are extra Frames, beyond the In, or Out Point of the Clip, but will not tell you if you have enough, predicated on the Duration of your chosen Transitions.
Note: This is how two adjacent Clips will look in Premiere. The display of the Clips will only be from In Point to Out Point, and the Handles will not be shown, but are still very necessary.
And another Adobe Help entry (some things repeated, but some added): http://help.adobe.com/en_US/premierepro/cs/using/WSE2A9B838-1422-4d8a-9A03-CFDF4332533B.ht ml#WS17A423FB-FEF8-4172-A7C8-8521D8CCB8C8