I would only purchase shears that say that they are designed to cut hair. Some scissors purposely have duller blade.. ie childrens scissors for art. That is not to say that you have to spend a fortune on them but I would do some homework before you make the purchase to trim your hair. It would be better to be safe than sorry.
But to your point, after you have purchased them for your hair, then use them soley for your hair.
I hope that was a little helpful.