Dewalt 735 planer

[Mark Brewer]

Use my planer regularly. Works well for what I need. But the last few boards were ok, but not great. So a little cleaning and swapping the blades.
Wow what an improvement, I guess you don’t realize how knives have worn until replacing them.

[Jim Becker]

Aside from immediately visible effects from nicks, planer and jointer knives tend to wear with some level of stealth and the dull sneaks up on you. Sometimes you might notice a difference in the sound when cutting; sometimes not. In many respects, we each have to learn out own machine's behavior relative to how frequently/hard we use them to judge when to consider a "regular" knife replacement.

[Mark Brewer]

I do agree with regular maintenance, and yes the sounds are quite different with sharp knives.