Fishing logs are a great asset, for the many reasons listed by pillcaster and fishndave. I use this one that is internet based so I dont have to worry about computer crashes and I can accsess it from any computer. It is pretty basic but alows you to ad/save entries of river names, and flies. You can add pictures. You can also search your log by, river,month, insect, or even by year. I used to only make entries on good days now I make them for every trip, including my still water trips. And its free