I was going to answer a question on how to learn pronunciation without help from native speaker - which I did - but then I wasn't sure if I should do it because my primary base is my own experience. I did give the same advice to some friends but none of them tried my method. I also see that other answers are mostly based on some solid and recognized source. So, should I answer with my own experience?
Should you use your own experience? Absolutely!
Should your answers be based primarily on subjective experience? That depends.
Now having said that, if a question is framed such that a personal opinion would seem to make for a valid answer, it's likely a poorly-formed question in the first place. Let me address this first, then I'll offer some examples of when and how it is and isn't appropriate to answer with personal experience.
Q. Is technique X useful for learning a language?
A. I used technique X, and I learned my language in 2 months!
A personal experience answers the letter of the question, but doesn't really answer the heart of the question. But the fault here lies in the question. It ought to be reworded:
Q. How is technique X useful for learning a language?
A. I used technique X, and it was useful in learning a language because...
That simple question re-wording not only changes the question, but the entirely nature of the answer. Now, your personal experience must be expounded upon to offer the actual meat of a useful answer.
So lets now assume that the question is well-formed, when is it appropriate or inappropriate to use personal experience?
Q. Are there any studies examining the effect of X on language students?
Unless you're a research linguist who has studied this field, your personal experience in the area of X is probably irrelevant to this question. Even if you have a lot of personal experience with X, unless your experience is part of a study, it's not relevant to the answer, no matter how "true" your experience is! The question is asking for studies...
Q. How can I overcome struggle X when learning my language?
This is a perfect place to offer experience-based answers. When I ask a question like this, what I want is the experience of others who have had the same struggles. This is an example of "good subjective."
I want answers like:
A. When I was struggling with X, I found that A, B, and C could help.
Experience is one of the sources of knowledge
Academic studies are more trustworthy than our experience because they are done and reviewed by professional, in-field researchers, which are made by their reputation. A reputable speaker tends to say correct thing than a lower one, but when we talk about knowledge, their reputation is unrelated. Of course if you have studies to back up what you claim, by all mean use it. But if you don't, then it's fine, as long as you provide enough thinking about it. After all, how do knowledge from the authorized sources made from, if not stem from experience? By asking questions, especially the how and why ones, personal experience will be refined.
Usually, personal experience will only describe the surface, the what or the how to of the object or the process. But usually, for the questions that asking for technique, like the question the OP is about to ask ("how to learn pronunciation without help from native speaker"), these answers are adequate. It is always best to provide the how or the why, but simply talking about the what is enough to satisfy the asker. If we need to know more, we can always comment to ask, or even make it a separate question.
What you're describing might be what closing questions as Primarily opinion-based is trying to avoid.
"Experience" is broad and unclear. There might be some expertise in what you're suggesting, but it might just be your opinions. I can't judge objectively unless you have actually posted your answer. It's up to you now to post or not, but here are some definitive tips:
Do: It's best if you do provide a link to some source that agrees with what you say. There's no need for extensive quoting if the source agrees with you.
Do: Consider whether the question is likely to attract opinionated answers. If it does, flag as such for closure.
Don't: Don't write anything in a comment! If you're unsure it's good advice, and it turns out to be bad advice, it can't be downvoted, and it will always appear before answers. Also, let's moderate comment-answers more strictly here, before they start spreading like a plague.
Because language learning is essential an individual endeavor (what may work for one person may not work for another), I feel that providing experiences that aided in your personal learning should be accepted. I would add a provision to this though. The experiences should have some repeatable steps and/or reproducible effects given a certain circumstance or environment. Or there is a reasonable rationale and/or logical progression as to why one might want to rely on the experience.