Texture parameters, can be specified only once?

Hello, I have a question about the calls to glTextureParameteri(), the function used to set mag and min filters, texture wrap mode etc.

Can the calls be made only once (when the texture is first binded), so the parameters are stored with the texture. Or do you have to specify them every time you change the current binded texture (i.e. you bind the texture, then set parameters, then draw)?

They are part of the texture object. Or, as with 3.3 and above (or anything that support ARB_sampler_object) stored in the sampler object.