I had a pair of pinking shears still in their original case for only God knows how many years and rarely used them and I know I hadn't used them in 14 years since my last move. I gave them to my sister though she'll probably never use them either. I prefer the pinking blade for my rotary cutter and I use it quite a bit. Just last week I used it on my black sateen fabric I'm using for the quilt I finally took off the design wall and finished. Sateen fabric seems to fray so badly and as it might be months before I get back to the quilt to quilt it, I didn't want the border to fray on me. I love that blade and made sure I have an extra one in case it goes dull on me at the most inconvenient time. Also have the blade that puts cuts every so often for when you want to croquet on fabric, it puts the cut perfectly and evenly for you. Used it recently for a friend that wanted to add croquet to the edge of a baby's quilt she made. She said it worked great for her.
I use my pinking blade whenever I am sewing clothes as it just looks nicer to me............that is if I'm not serging the edges.