I was taught quite some time ago that probably the most important monastic virtue is perseverance. I think that's true of spiritual practice whether one is a monastic or not. What really counts is not throwing in the towel. Here's an observation that will help:
It's like in the great stories, Mr. Frodo. The ones that really mattered. Full of darkness and danger they were. And sometimes you didn’t want to know the end… because how could the end be happy? How could the world go back to the way it was when so much bad had happened? But in the end, it’s only a passing thing… this shadow. Even darkness must pass.