I've been using these sheet protectors for years to organize and save printed patterns for my crafting business. I have binders full or them. They are extremely sturdy I'm constantly paging through patterns and I've never had one tear.
I use this product to protect completed pages in my stamp collection. The sheet protectors are archive quality and acid free and so are excellent for protecting my collection. Additionally if I have to change something on the page access is relatively easy.
I use it as a music teacher. I'm working on a high school musical and often I need to mark up the music change keys cut out sections etc. This is an ongoing process and my changes often needs to be changed. Rather than mark up the actual music I use Vis-a-Vis wet erase markers on the plastic and it can easily be erased and changed.
I make copies of embroidered cards I make. So when One pattern wears out I have another I can use right away . NO WAITING. Also I return the used pattern back to the sheet protector. Also use them to save free idea sheets for jewelry making and crochet.