repetition

So today's question is... when does repetition of a theme, a motif, become recognizable as a deliberate aesthetic pattern, or boring lack of inspiration, or obsession, or thoughtful variation, or or or or or...? For this is far from being the first vase with stems in water that I've included on this blog this year, or the first vase.jug with a handle. Clearly, I could answer by saying - look, it comes to the end of a day; I have a photo to take...what's around me...? But this is not the only picture I've taken today - and even suppose it were: why choose this theme rather than another one? This forces me back into my own grounds for aesthetic pleasure, at least as exemplified here: ambiguity (of depth, solidity, refraction); intensity without brightness in the color; near (but not exact) symmetry; a certain academic preoccupation, perhaps, with issues of surface and depth. In other words, one of the things that a repeated subject makes one consider is, evidently, one's personal, non-thematic specifics of visual preferences.