As far as wiping out two hard drives goes, I was using some Maxtor installation software. I followed the instructions to the tee, but had two hard drives plugged in and they both got formatted while I was only trying to format one. It must have been some sort of internal connection or something, but I did not instruct it to do that. Since then, I always isolate drives, especially while doing installations, it's fail safe.
It's not really a big deal or much wear and tear and I only switch them back and forth on rare occassion and while doing setups. So it's not really a problem for me.