Daggers have most often been considered a secondary or even tertiary weapon and they have traditionally been used primarily for combat. However, there have been periods where the dagger was looked upon more as a tool and a weapon rather than as just a weapon. I must admit a personal bias here: I love daggers! I use daggers like knives. I’ve even field dressed and butchered game with them. I craft my daggers with an eye towards utility as well as combat usefulness. I make my dagger blades just a little wider and the bevels just a little more acute so that there is a pair of useful slicing and chopping edges as well as the very deadly point for thrusting. I carry my dagger almost everywhere with me.
The symbolism of the dagger has traditionally been either that of surreptitious and scandalous assassination or courageous and brave desire for close combat with the enemy. Their carry has also symbolized rank much like a handgun worn by officers in the military in more modern times. In use they are usually thought of as primarily stabbing weapons having two edges as opposed to knives which are thought of as cutting tools with a single edge. In practical application however the lines of what makes a dagger and a knife separate are often blurred.
To me, two edges means that I have a ready backup if one edge gets dull or damaged. Most of my personal dagger blades are about 8 inches in length and about 1 ¼” inches wide with a thickness of 3/16” to ¼”. This seems to be about ideal for me combining moderate length with utilitarian edges and plenty of strength. I admittedly beat the snot out of my personal stuff on a virtual daily basis. This does however show me what my stuff can do, and that is quite a lot!