Once you walk away from some aspect of holiness you can never return. You can try to go through the motions but the inner essence never returns.
 I walked out of the Mir in order to go to Israel. Though I succeed and even did well in some ways--still  the essence of the Mir --the light of inner holiness of learning Talmud in depth I was never able to catch up with again.  Even the fact that God granted to me a few ideas in Talmud here and there only came about because of my learning partner. Same thing when I left Israel. Though I tried to return but I never could and that light and holiness that was part of my first stay there also never returned. The lesson is: if you have something good, hold onto it with all your might. Don't think it will follow you around. [That is at least the lesson for my kind of soul. There are several different types --so my advice here might only apply to me and similar kinds of people.]