Can we just say giysi for clothes or giysiler? Is clothes always treated like a plural in turkish?
Depends on the context, really. But I'd say the plural giysiler will be used most of the time when you want to indicate more than one item of clothing.
It could be translated as our wardrobe. In northern Ireland we say our wardrobe when referring to our clothes
Hmmm...we do say the same in the US. It is a fine translation and will add it. :)