Prospective memory failure

Ok so I just wanted to know the importance of a reliable prospective memory in auto-suggestion. I've noticed that my prospective memory is particularly poor in that I forget to do so many things unless someone else reminds me or I write down a reminder for myself. In fact it gets in the way of my dream recall because when I wake up, I can remember 4 dreams at once. And I tell myself to remember to take notes of all of them. But then I only note down 3 of them, and sometimes I even forget that there were 4 in the first place. I sometimes get memory lapses as well where I forget the names of some of my teachers and the like.

So first of all I want to know the importance of prospective memory for auto-suggestion.
Secondly I want to know what can affect the prospective memory.

I know that heavy smoking and drinking affect it negatively, particularly during the formative to teenage years. As a teenager, there would be days where I would drink large amounts and have horrible hangovers, but this was not a regular occurrance. Anyway I'd like to know if this has long term affects on the brain.

EDIT: I just realised I forgot to drink my tea :( it's cold and bitter now.