We all deal with lost stuff and you will experience it some day unless you have backup arrangements used by banks and governments. When you hit erase or format on your camera, it only takes a few seconds to format. You're only marking them ok to overwrite with new pictures and they're not actually erased until they're overwritten.

A full wipe down buffs everything out and it keeps garbage from floating up if you ever need to recover stuff. This takes about 10 minutes on a common 8GB card. The larger the capacity, the longer it takes.

Large memory cards don't give you any benefit unless you need the capacity for long HD videos. I stick with 4 and 8 GB cards. Battery life is always the limiting factor for me.

You will peel back the tarp and start looking around when there's a need to recover files after a corruption or accidental deletion.

A card that hasn't been wiped down comes up like this as remnants of everything that you purposely deleted also float up. Going through all the bits is a nightmare. The process is painfully slow with an 8GB card. A full scan on a 64GB will take many hours.

That's pretty clever. Using secure delete tools as a means of aiding file recovery.