I'm interested in genealogy and family history and use these sheets to protect the information that I have printed for the family and for friends. The sheets are easy to use and facilitate the turning of pages and also protect them from wear. I find that the mediium weight is really quite sturdy and stands up well for the use intended. I also use them to store folded charts and photos etc. in the notebooks created and always buy the package of 200 because it is more economical as I use so many.
I've been using these sheet protectors for 5 years. They are sturdy and serve the purpose for protecting the pages beautifully. Knitters and crocheters really appreciate these for their patterns. You can use highlighter tape on them and keep patterns clean. I also have organized my recipes in 3-ring notebook using lots of sheet protectors.