The requirement to have multiple passes of writing zeros and / or random data to securely erase a HDD is largely gone.
15-20 years ago, the areal densities of HDDs were such that it might - by using highly sophisticated tools - have been possible to extract meaningful amounts of data from a disk erased with a single pass of zeros.
It's simply not feasible to recover more than a tiny fraction of bits on today's HDDs, and that is insufficient to extract actual data.
So one pass is fine for most situations where the potential value of any recovered data is far, far less than the cost to attempt to extract it.
And if you want to render the disk truly useless, dismantle it and shred / smash the platters to smithereens, which has the side effect of being rather therapeutic.
SD