Knowing whether or not the blade of your hand saw is dull is essential for ensuring that it performs at its best.
Counter-intuitively, one of the signs of a dull blade may be that it seems to cut through wood too easily as this could indicate that the blade is not providing an adequate amount of friction while cutting.
Another thing to note is whether or not your hand saw is leaving rough edges along the cut line, as a sharp blade should provide a clean cut.
Lastly, you can get a sense of how dull the blade is by holding it up to the light and examining it closely – if the blade appears jagged, then you know it requires some sharpening.