I always do my own research when I ask a question, and I check cites to validate their answers as well. Sometimes they find info I didn't.
How Do You Know When To Accept Feedback From Another Source?
I would think that when it seems that the resources that you have at hand have exhausted themselves, and you aren't getting anywhere, then you might welcome feedback from an outside source, and ponder it without being objective. You should welcome all avenues that are presented to you, and then if there is something that might pan out for you with the feedback, then go forward from there. Hope this helps, good luck to you.