I differ from Tee Gee in that I don’t routinely dig at all but rely entirely on mulches. I find it convenient to mulch as many areas as possible at this time of year with whatever matter I have available - compost, rotted woodchip, leaf mould or horse manure. I then cover any bed which is empty with black plastic. The mulch continues to rot down through the winter and begin to mix with the top layer of soil. On removing any plastic when the bed is needed in spring, there is the black gold beneath. If the mulch is homemade compost I quickly get a flush of annual weeds so tend to wait a couple of weeks for them to germinate and be removed before any direct sowing.
So in brief I’d say that my way to retain soil structure is to mulch regularly, probably about annually.
