The editing and image processing for my second book is almost at an end and it should be at the printer within the week (please) and it's time to think about photography again. One of the things I'm going to do is to make sure that I have more than one project in mind. There will be days when any given project isn't practical - wrong conditions, not enough time, lack of inspiration, subject not available, who knows. Further, any project that you involve yourself in intensively tends to come to an end at some point. Certainly that was the situation with Independent Machinery - after about 17 visits, I felt I had done what I could do. Doesn't mean that I might not check back with them a year later to see "what's up" but for all intents and purposes it has wound down. If you don't have some ideas or already a prolonged project on the go, then you could be in trouble.
For example, I'm starting a project on wind - capturing things that move in the wind - whether it be plants or flags or clouds or hair or water, but obviously that requires windy days, so I'll need a minimum of one and far more likely several other short or long term projects to keep me going.
How many projects do you have on the go at one time, both long and short term? Do you ever find yourself frustrated with nothing worth photographing?