I'm presently finishing up my first calendar year of studies in graduate mathematics, and I would be lying if I said that I didn't often refer back to Math SE when trying to solve problems that were particularly challenging for me. In fact, there was a question on one of my recent qualifying exams that I was able to solve using techniques I had seen from answers on the site. However, I am also aware that, if left unchecked, SE can become a crutch for doing homework, which is ultimately detrimental.
More to the force of my question: What would regular users and educators on this site recommend as helpful for a developing mathematician's (such as myself) relationship to SE? Are there healthy boundaries that should be exercised? Should a graduate student use SE only in the most difficult of cases, or is it more beneficial to spend time looking at others' techniques for solving problems and learn from them?