It was about $600 to replace them on my 1D Mark IV. That was close to what a used 1D Mark IV costs. Yup, over the years I've had 2 mirror boxes fail and only 1 shutter fail. Canon usually suggest replacing the mirror box, when its due, but unlike the shutter life, I've never seen a published life expectancy for the mirror box. Depends on what the cameras cost. When I bought my first 1Dx it had 200K but it was really cheap at the time. I called Canon to get an idea what a shutter replacement cost in case it failed the next day. Was told at the time it was about $300 so even with the $300 factored in it was still really cheap so bought it. Shutter rated lifespan depends on a concrete camera model. The modern entry-level cameras are usually rated for something about 100,000, while professional-grade models can go up to 400,000 actuations. Just to name a few: EOS 100D, 200D: 100,000 actuations EOS 5D Mark III, EOS 6D Mark II: 150,000 actuations EOS-1D X, 1D C: 400,000 actuations Canon 1DX Mark II Review - 1DX Mark II Specifications. Photo News. News. Photo News; New on the Site; News Archive; Shutter Speed Range: 1/8000 - 30 sec: Bulb Mode: Yes: Unless you need the built like a tank and weather sealing of the 1dx II, I would buy the R5 or R6. The R5 will give you better weather sealing than the R6. I replaced my 1dx II with an R5 + 100-500 for wildlife and have no regrets based on 17 days shooting in YNP/GTNP. I rented an R6 as a backup for the R5 and used my 100-400 II with no issues. Image quality is surpassed by much cheaper cameras. Nikon puts D5's AF capabilities above everything else to the point where cameras that cost less than half the price (like Nikon's own D810) have clearer, sharper images with higher dynamic range and higher resolution. Pro. The big boss is back for round two: the Canon EOS 1D X Mark II is the company's top-end full-frame DSLR, which replaces both the original 1D X and video-focused 1D C models. "My camera is rated for 100,000 shots, but since I purchased it refurbished, maybe it already had shots on it?" I highly doubt your camera had very many clicks when you bought it. kAhG.