Several thing did it for me.
New toy, but started at my laptop, then mobile, later tablet and now ereader.
Hate books fill so much in my home, and we have traveled some times the last years, and several books weight too much when flying.
And my arms doesn't like to sit / lay down holding a book in the air.
Ohh and my decision from tablet to ereader was again new toy, longer battery life,weight and reading in the sun