"reduce the possibility of fragmentation"
You got our jist Groucho. I think what your saying is good for smaller cards (2GB and less). Fragmented or not, there's not a whole lot to read through. But my 8GB Extreme III (and confimred by many others) is significantly slower (reading and writing) when used often without formatting.
We can't fully put the blame on the card (afterall, the cameras are usually the bottleneck), but we do know that formatting helps with the issues. I don't think a low-level format is necessary though. Just let the camera do it each time you empty the card.
Well, based on a little research, I could only find a few anecdotal stories, no hard test data. Frankly, I'm not quite convinced. Especially because flash memory does spread out the data across the whole memory (unlike hard drives, which usually write sequentially in order to minimize head seeking and access times), I'm a little skeptical. But as I said, formatting is pretty painless (usually a second or two in-camera) and has few if any drawbacks, so I certainly won't say that you
shouldn't do it. Heck, I'll even concede that there may be slight performance changes but I would bet that most of the observations are more subjective and probably wouldn't hold up in double-blind testing.
You need to format your memory card often... especially if you do a lot of selective deleting on your camera. Not only can it enhance performance and prevent corruption, but each time you 'delete' a picture it's not really deleted. It is partially erased, leaving a digital fingerprint so to speak. Those fingerprints add up and can jam your card eventually and it's very expensive to try to have recovered. Our store charges about $100 for 1GB of image recovery. Formatting your card give it a clean slate.
I don't think I agree with that. Yes, deleting a file only deletes the file entry pointing to it, but formatting doesn't erase any file contents, either.
There's no "recycle bin" or similar on a memory card. As soon as you delete something, that space is available for writing. Assuming that your concern is avoiding fragmentation, the issue is not deleting files, the issue is deleting files in the middle of other files that are retained. This might happen via in-camera deleting, but generally, anyone loading their pics onto their PC will move
every file on the card, leaving it essentially blank. At this point, there should be no difference in which sectors are free for writing versus a freshly-formatted card. The FAT table will retain references to the original files, but there will be nothing left of them once new files are added.
As for the idea that "fingerprints" will "jam your card eventually" and the card will need an "expensive recovery" - well, that's just plain untrue and installs an unnecessary level of FUD into those who don't deal with file systems for a living. Memory cards need recovery work because of physical failure or user error (accidental formatting/deleting, removing the card while it's being written to causing corrupt files)... memory cards do not need recovery work because they weren't formatted enough.