If I have a problem and someone suggests a fix, I try it and let them know the results. If several people all chime in with the same advice I'll thank them all in one post and also post the results.
The things that irk people who take the trouble to respond the most are when you recommend that a person try "A, B, and C" and they post back "I tried A and it didn't work!??" (What happened with "B" and "C" - nobody knows...) Even worse, they post back "my friend said to do D, E, and F, but I'm still having the problem. (What happened with "A", "B" and "C" - nobody knows...)
Then there are the ones who just disappear. You assume that they got the problem fixed but you really don't know. You also don't know how
they got the problem fixed, assuming it was. Every problem solved has the potential to help many other people when they stumble across a "Solved" thread while they are looking for an answer to something.
The bottom line is that the people who are trying to help someone like to know that their advice is at least being tried.