Manufacturers claim to have 300,000 write cycles. Since I don't believe any manufacturers' claim, I would not put in more than 100,000 cycles for SLC and 25,000 cycles for MLC (multiple level cell). MLC stores two bits (noise margins lower by factor of 4). I have tested and burnt CFs at less than 10% of rated write cycles. Now, for the bad news. Unless you are paying premium, most CFs over 256M are likely to be MLC. So far, we have return a couple of 512M and one
256M for failure, even without any major stress test.Our advice: use an older and smaller main CF (128M or less) and use bigger CF as secondary and absolutely read-only, unless you are in the business of testing and selling CFs like we do. So far, manufacturers are good at handling returns. If you are not buying directly from manufacturers, make sure your dealer will handle returns properly. You will need it.