If you are concerned about edge retention, you need to choose your knife steel carefully.
There are several steels that rate very high on edge retention.
However, the downsides may be ease of sharpening and initial cost of the knife.
With so many excellent sharpening systems available today, I consider ease of sharpening
a low value issue. Look for M390, CTS 204P, ELMAX, CPM S35VN, and similar steels if you
want good edge retention.
I have a Benchmade in M390, and it is incredible in the field. Dave.