Comparable sales are useful only after the material differences have been made visible.
Distance and recency matter, but they do not settle the question. A sale on the next street may have different land usability, natural light, traffic exposure, layout, condition or development constraints. A slightly older sale can sometimes provide better evidence if buyers would have considered the two properties genuine alternatives.
I begin by asking which past sales competed for the same buyer. I then adjust the interpretation for the differences that buyer would have noticed and priced.
There is no perfectly comparable sale, and an adjustment is still a judgment. The aim is not a precise number. It is a defensible range and a clear account of what could move it.