Many times I feel like giving advice; especially when I have handled a situation better than some one or when I think that I have handled better :-) I am sure you also have felt an urge to give advice.
May be your advice is very valid and will save the person from a disaster. However, the hard fact is if you give advice without a request for the same, you are the loser in any case. One of the following will happen.
1. Your advice is ignored and not respected - This probably is the least damaging option. You might feel hurt if you know that the person ignored it and wait for your chance to bounce at him with "I told you" drama.
2. If the person follows your advice. They would want you to own up the result. If something good happens, then it becomes their intelligence that they followed this idea and if it turns out to be other way round, then you have spoilt their life / plan etc and they bounce at a you with "Only because of you" drama.
In any case they see you as a controller or an intruder. So even if some one seeks for advice, it is better to give a few options and ask them to take a decision and ensure that they understand that it is their decision and not yours.
You might be wondering why am I giving this advice while I recommend not to advise. You will reach this blog only on your personal will and you will read this article only if you want to read. This very fact means that I am not giving this advice for some one who does not seek for it :-)
I understand what is going in your mind!!! "Was she able to follow this always?" is the question running :-)
The honest answer is a BIG NO. Many times I have given unsolicited advice and got hurt. I have vowed to myself many times that I will not repeat the mistake :-) I am able to practice this with people outside my immediate family. I am still trying to implement this at home and not successful yet!!!