If you are doing freehand drawing/sketching, do not use the 14B Pitt Matt, because it gives the same tone as the 12B but has more gloss!!! Because, one way or another, it is a relatively hard graphite, even in these numbers, and because, one way or another, the correct technique is to shade with the side of the tip and avoiding putting too much pressure on the paper, but on the contrary, we should simply pass the pencil more times, if we want a darker tone, so, the 12B, can easily give the tone of the 14B, having saved a lot of gloss!
P.S. Yes, if you do not have the appropriate experience, you will try what I described and you will find that with a little pressure, a dark tone does not come out. It is until you find the right ratio of pressure and passes, that each shading will need!
P.S. For sharpeners, the "KUM longpoint" or "Longpoint auromatic" (for the more advanced), is what you need for these pencils. For the harder tones (H, HB, 2B) I use the KUM Masterpiece. Expensive but the blades last for many years, they are sharper (so the tips do not break) and generally the quality and the tip they will give you, cannot be compared with any other sharpener! Only manual with crank or electric ones can give such a long tip, but with those, you have a bunch of other issues, so I avoid them. Since we said it all, for eraser I use the Faber Castell Dust Free 187120 (by far the best!!) LYRA kneaded eraser and paper, Hahnemuhle Dessin 150 gsm (incredible feeling, good for beginners) For more advanced: Arches Watercolor be careful to be (Hot Pressed) the one that is black and has a pink square on top that writes the brand type etc. For Sketchbook, Canson 180 Artbook or Canson Universal (they have exactly the same paper) if you can't find any of these, the next solution is Hahnemuhle Sketchbook 120gsm (be careful the company produces many different sketchbooks, ask for the one with 120 grams paper!)
I wish you a good time!