I've been archiving some of my past entries on my livejournal to a private archive I use to keep track of my experiments. What stands out to me is just how sloppy I was a few years ago in keeping tracking of some of my experiments...that and also the fact that I have a lot of experimental work I need to develop further than where it currently is at. It's very important to keep a record of the work you are doing. I wish my earlier records were more comprehensive than they are...I'm fortunate that I have a paper record as a backup in the work I'm currently archiving. However, there's still a few missing details and those details count for a lot.
In many magical books the admonishment of keeping a journal is offered out so that you can keep track of your results and process. I can't stress enough just how valuable that advice is, because no matter what you read in a book, it's what you write about your own processes which really informs the efficacy of your work, and speaks also to your discipline or lack thereof.