yarn label questions

[catwoman]

HI.Does a person have to go by the fiber content on a pattern and yarn labels?

What do you think?

[Granny Square]

I thought this was a duplicate post, but  this is a different question than your earlier gauge question. 

My answer is 'it depends'.  You can sub as your heart desires BUT just need to be aware of the fiber content behavior, and ensure it is appropriate for the use of the item. 

What you don't want to do is mix fibers in a project(could be a disaster if they have different laundering features), and you don't want to use acrylic for a pot holder (it could melt or burn you; cotton or wool are ideal for heat).  Also, acrylic may not be the ideal thing for something that needs to be aggressively blocked.  Cotton can be tricky for wearables because it stretches out as you wear it (goes back to shape when you wash it; I understand linen is the same way).  You probably wouldn't want to use scrubby yarn for a  scarf (unless it's a gift, and you don't like the person...kidding!)

[redrosesdz]

I agree that it depends. However, there's nothing wrong with experimenting. I've used different textured yarn for patterns that called for standard plied yarn with mixed results. (Using different textures is similar to using different fibers.) I've made some chenille items that turned out beautifully. I've also started projects and after a while realized that the yarn wasn't right for the pattern. 

What do you have in mind? It sounds like you picked a pattern and found yarn that you like, but they don't match. What's the pattern? What's the yarn?