Headphones always crap out

[Mangudai]

I guessing its because their cheap 8$ "street" style ones but could it be normal wear and tear? I listen to music a lot when im working ripping and running around and lifting heavy crap. I notice after about 3 months or so one ear on the headphones only works if you jingle the wire properly then it stops working completely. Is this because of the headphones or because of abuse? What I really mean to ask is does this happen on "mid-high" level headphones?

 

[Nenu]

Either a wire has come unsoldered or is broken.
Most likely a broken wire, cheap earphones often dont have very good stress relief for the wires and even good earphones fail like this.