whenever you make an equipment change. When I went from MF to AF, I ended up buying AF lenses and an electronic shutter release. When I switched to digital, I had to change to a "digital" electronic flash.Last fall, I had an opportunity to upgrade to a high end, large leg diameter, carbon fiber tripod. One of things I immediately noted was how much more solid and rigid the new legset was. Over time, that new firm base has begun to illustrate the shortcomings of my Bogen ballhead and QR system. Just recently, I gave up that system, for a new Arca Swiss type QR system, a much larger diameter ball head, and a Kirk Enterprises L bracket. It is all so much more solid and yet all lighter and more compact than my former equipment. I am looking forward to getting some use out of it.