Often, when somebody visits my workspace, I am met by polite laughs when they discover how many album sleeves I have designed, but not written music to yet. I guess they compare it to schoolbands who use more time discussing how they are going to spend the money they earn as rockstars than actually practicing.
That is, however, not how it works for me. I have always thought that the visual artwork was just as important as the music. Great music could give me a bad experience it the cover did not do the music justice. My personal favourites has always been Storm Thorgersons works for Pink Floyd. Storm has worked with a lot of other artists, but has never had the same impact as with the Pink Floyd sleeves. I love the cover for 'Wish you were here'. An album I consider as Floyd's finest. Other great sleeves includes Einstürzende Neubauten's 'Silence is sexy' and 'Haus der Lüge', Jean-Michel Jarre's 'Oxygene' and 'Equinoxe', Nine inch Nails' 'Ghosts' and 'The Fragile' and not least Massive Attack's 'Mezzanine' cover.
When I start working on an album, I need a focus in order to know in what direction I'm going. As I try working in a new genre every time I record an album, having a musical focus is very hard. Normally during the working process I analyze and absorbs a genre, and it is a learning process every time. A visual focus, on the other hand, helps me a lot better to steer me in a certain direction. This means, that the sleeve is designed at a very early stage. The artwork for 'Constructions' was created before the first song was even written. If I had not had the cover all the way through the process, the album would not have been nearly as coherent as it is.
This, of course, means that I also have artworks for abandoned projects. Musical excercises that were going nowhere.
Like the Kraftwerk-ish 'Pictogram',

the 80ies King Crimson-ish 'Foul Play'

and the recently abandoned 'Evenkia'

Recently this passion for visuals has drawn me into the world of directing. This takes a lot of my time, and I am not as devoted to music as I have been. But I do have a sleeve for the next one...