I kept a pregnancy diary, and once DS5 arrived I just kept on writing, so I have a pretty complete record of his development and interests (which is already fun, and which I anticipate passing on to him some day!). It was natural to write down words we heard, to start with. Once he was really beginning to talk I started a real list, but I stopped it once I got to 100 words, i.e. I was only actually keeping a list for a few weeks. I suppose it would have been interesting to see what order he learned words in even after that, but it was already clear I was missing things and the effort didn't seem worthwhile! I did continue to write down the odd utterance verbatim.
