Broaching a big clearout now, one that I've been avoiding for some time. Main deciding factor will be utility, as I have a very good idea what I use and what I don't.
A few flies spoil the ointment, namely pieces of kit that is just so beautiful, or of low resale value, or kit that would have value as backup.
The last is the most insidious - the backup factor, as I am no pro, and shoot for my own pleasure. Even the not to be repeated photo opportunities that come my way, I still have other systems that could serve as backup. For example, I'm having trouble selling a second tlr body, in addition to a second M body, despite the fact both gather dust.
I find it easy to indulge and buy cameras, as generally I buy new cameras for the different ways of seeing they afford me, or the different kind of image output they give me. All this makes it difficult sometimes to decide what to get rid of, but I'm a minimalist at heart, and seeing a shelf of unused camera kit irritates me 🙂