Reading habit

I'm an advocate of reading habit but I must admit ive become a poor reader over the years. I'm not able to figure out why. That said, I still enjoy reading although I don't devote much time for reading. It isn't that I don't have the time. From time to time I do make an effort to read a book and complete the reading in matter of several days unlike the younger days when I used to read more than one book a day. It is a fact that after completing a book I hardly remember much of what I read. It is quite embarassing to me not being able to recall the characters and the story. Why is it so and how to be a good reader at my age?