Just a random example of a "Beater" knife
The answer is simple.
You will not be afraid to get it: dirty: scratched; blunt/dull (at times, often maybe?); and simply use it rather than look at it.
In fact owning a "beater" is a good way to convince "anyone" that the money was well spent rather than having a bunch of knives that stay in the drawer and only come out at "show and tell" times LOL!
What is a beater? Is it a Bark River beauty which is just too good to take out hunting? No, a beater is anything but. This is a knife which will get used often. It may not even be a fixed blade but a favourite folder.
You will never be worried about using your beater because the beater is not for resale, the beater is not for the collection nor is it for your grandkids to inherit or even your own kids to inherit. A beater can be lost without having a nervous breakdown, a beater will have countless stories attached to it.
A beater, you will become super adept at sharpening techniques, a beater will serve you well.
Another great beater for me, my Extrema ratio MK2.1!
A beater will be simple to clean, a beater can be left outside (although I would never advocate leaving any "sharp things" outside!
So what constitutes a beater?
Well it just can't be mega expensive* otherwise you will never use it, seriously!
A beater's scabbard you will not worry about it getting dirty or wet. (you should still care for it)
It must be easily accessed and easily carried otherwise you will never use it.
A beater, you may even loan out to your best friend LOL without fear.
If it gets stolen you won't cry tears of blood because you lost a 500 buck knife to carelessness.
A beater is something that you can take out on a picnic with friends and not have to embarrass yourself or boast about how expensive your beater was because it will still carve that BBQed meat just as good as that 500 buck knife sitting back at your home (thank god you left it there not to embarrass yourself when your friends say, "my SAK can carve that meat just as well, let me show you"!).
* (depends upon what one's disposable income is, will determine what is classed as "expensive" ).