Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Once there're gone they're gone...

They are high quality, idiot proof to use and will drill steel nicely, but they can't be re-sharpened (well mabye...). I've tried by hand but there are to many angles and surfaces to deal with to get them right in a timely manner. Sharpening a regular drill bit is hard enough. If they would make a bit sharpener that would sharpen these (and not cost way more then a drill doc) I would continue to use them all the time and not have to buy new ones. Now I only use them when I'm drilling something vary rounded or when I can't find a small bit to make a pilot hole... not worth the money if buying for a long term use in hard material.