Most people that think they know something will tell you, at least 35 passes of various bit patterns are required to be written to each sector on a hard drive to securely erase all content. If you only wipe it once, it is possible using a MFM (Magnetic Force Microscopy) to recover data, and that it is even possible to see a history of data as each layer of data can be recognised by its age.

This is complete nonsense. A single pass writing all zero's or all 1's are sufficient to completely wipe an old or modern magnetic hard drive so much that the statistical probability to recover any meaningful data is about zero. There is a moderate probability that one bit of information can be recovered, but this dwindles quickly to very near zero as more data is attempted to be recovered.

Since recovering one bit will not help anyone, for all practical purposes, wiping a drive with one pass of writing 0's or 1's will clear out all data and nobody will ever be able to recover it.

See details here.