[DanBC]

> and the government had tools that could recover previously overwritten data.

That wasn't true. But, since we can't prove it's not true precaution says you should over-write drives a few times with pseudo random data.

SSDs are a bit more worrying because end users don't have full control.

But with physical drives or SSDs if the data is that important you should be looking at physical destruction, rather than just over writing.