When I was "younger" I experienced extended periods of photographic inactivity, sometimes extending for months--maybe what most posters have described in this thread. Most of the images I made then were spur of the moment, technically well executed but lacking any unifying theme or purpose. I traveled for my work, and that provided a rich source of images. I lived in urban areas, which also provided lots of opportunities for "street shooting," etc.
Several years ago, I retired from my "real job" in order to spend more time studying this thing called photography and maybe making "better" photographs.
Since then I have had very few periods when I didn't make photographs on a weekly basis. One thing that changed is I no longer make photographs "of things, places, etc." I make photographs "about things, places, ideas, emotions, ...." Thus, these can be concrete, such as historic structures, or more abstract, such as the state of public spaces in both urban and rural areas.
Presently, I have several of these "themes" or "topics" that I refine and maintain in notebooks. From these notebooks, I devise shooting scripts, plans: where can I find settings, etc. that provide visual evidence in my continuing investigations. I pair these images with additional notes about concepts for books and exhibition prints ..., i.e., materials and places to show these images.
This is all a work in progress, but so is life.