Planer blades are generally sent out for sharpening, you could do it yourself but probably not worth the effort to invest for the 3-4 blades a year, generally have 2 sets so you can swap out and send the dull set out. Setting knives isn't that difficult just takes a little quiet time. The disposable blades are handy but seem to dull sooner. Carbide insert heads are quieter (a lot) and the inserts are rotated when dull so you get 4 edges before replacement. The spiral and helical heads do better on highly figured grain (helix better than spiral). Drawback is that you can't take as heavy a cut as you can with a straight knife planer.
Hope this helps
Chuck
