Over-explaining things

How many times should I have to explain the reasons behind something? Many times, about many different things, I've explained something. Then a period of time passes, and nothing happens and I bring the subject back up and I have to re-explain whatever it is again. And then nothing happens and a period of time passes, I bring up the subject again and still have to re-explain everything again. I go through all the reasons why something needs to be done and get agreement on the subject, but then nothing gets done and I have to fight for the thing again later.

In my mind, if someone talks to me about something, and I make a decision about it, that's it. I don't forget about it and not do anything, I remember the decision and I take an action. That doesn't seem to be the case here.

There are many instances I could explain, but won't. The main issue is that I'm getting sick of the lack of follow through and re-explaining things. I feel that I should be able to have one discussion with someone, and when we come to a conclusion on a given topic, that should be the solution and it should be put into place. I shouldn't have to go through the difficult discussion several time to get to the same conclusion.

So, what do I learn from this. Be a man of my word. If I say I'm going to do something do it. If I don't really intend to do it, then say that. Once I have a discussion with someone about a topic, I need to be able to remember what we decided on and take some kind of action on it.