Unless you are super strict with yourself and don't posses even the slightest hint of hoarding tendencies, chances are you have a few stray make-up brushes that you don't ever use? Perhaps said brushes were gifted to you, maybe they were part of set or they were bought with only good intentions and now gather dust; however you came by them, they simply aren't being used and I can't help but wonder why?
I use a lot of make-up brushes, probably more than I need to as I only have one face; those brushes I don't feel guilty about as like I said they are being used, it is my little pot stuffed with neglected beauty tools that hits me hard. The brushes I don't use are all of the same purpose - foundation and concealer, and both happen to be flat in shape. Now of course in the right hands, I am more than sure they work wonders but I deem them to be a cosmetic hindrance than anything else.
I've stated in the past for foundation application I have three go-to methods: my hands, a flat top kabuki brush or a beauty blender - all of which is dependant on the texture of the base product I am using. Goodness knows I have tried with other foundation brushes but very few deliver the results I am looking for, especially not a flat foundation brush. In my experience such brush is not only difficult and time consuming to work with but also prone to - in my hands at least - creating an uneven finish. Why do I keep such brushes in my collection? Sometimes I do use them to slick on cream contour and highlighting products, before blending our for precision but I never reach for a flat foundation brush for its intended purpose.
In the very same vain, I don't particularly enjoy nor use flat concealer brushes - yes I may grab one to gently pat on concealer before blending out with a fluffy brush or my fingertips, then again that is a rare occurrence. Much like the foundation brush of the same shape I find flat concealer brushes to be fairly problematic - streaky results with a heavier finish - and tend to leave them well alone. I fully admit that a lack of skill and patience could be to blame here but why force it, there are plenty of great brush styles out there that work for me so why become frustrated over a particular style?
What make-up brush if any don't you use nor rate for that matter?