Instruct: Classify Amazon reviews into positive or negative sentiment
Query: great knife, but mechanism wears out quickly

Have used several of these at work. We use them every day, but not all day and not hard. It is a great knife from comfort and ease of use. I like the easy retract button and a simple squeeze to extend. The autoload functioning of the new blade is great.But at the price, you go through them too fast. The mechanism for extending and retracting wears out pretty quickly. The mechanism get sticky to the point of becoming non-functional. Have tried making sure was lubricated and all that. No difference.It really is too bad that the feature that sets this knife apart from the field fails so quickly