DEPT has some advantages over mere C13 NMR.
You can get more structure information than a full scan C13 NMR alone. You can tell which peaks are a CH or CH3 (DEPT 135, positive peaks), which are CH2 (DEPT 135, negative peaks), and which are CH peaks alone (DEPT 90, positive peaks). You then compare the peaks to the full scan C13 NMR. What you won't see on DEPT 135 or DEPT 90 are the carbonyl carbons or the quarternary carbons, which means it's all about comparing the full scan of ALL peaks to the DEPT signals.
Pretty much like solving a puzzle and lots of fun, in a non fun kind of way.