As a photographer you should try new techniques and ideas and setup test shoots. You are only as good as your portfolio and your book should always be kept updated with new looks and trends. In my opinion a photographer should aways be shooting, a test can be simple or very complex depending on what level and how much money and time you have to invest.
For me it all starts with an idea, being inspired by a film, an advert, a magazine or even a work of art. My most recent test shoot below was a simple idea inspired by an Agyness Deyn shoot; I wanted some fierce portraiture for my book. I found model India Lownds and Makeup Artist Francesca Dalla-Riva who loved the ideas; we spent the afternoon working on these looks.