How many times before I get a unit without dead pixels?

I’m switching from Kindle to Kobo and bought the Libra Colour for Black Friday. I already exchanged my first unit because it had dead pixels out of the box. I open my new one today and voila - new dead pixels. Are all units like this? Should I just suck it up or try to keep exchanging? I bought it from Indigo in Canada and they told me I can keep exchanging faulty units until I get one that works… but is it even worth my time?