I think there has to be incentive or a way to see your accomplishments.
1. Show N Tell at my guild. They give achievement awards. And just showing a finished quilt which they will all admire is great incentive.
2. I keep a journal with pictures of all the quilts and other projects I've done. After a few years, it really starts to look nice and gives a great feeling of accomplishment.
Things like this help me stay focused on the tedious work.