Funny! A lengthy review of writing implements, and comments about them, without a single mention of mechanical (clutch) pencils. Like the Pentel P205 (0.5mm leads), and various other sizes of pencil and leads available. Vary the lead diameter and hardness to suit the use. Personally I use 0.5mm, 2B almost always. For technical work, where it's nice to be able to erase mistakes, they're perfect. For daily personal note taking, the erasability is fairly irrelevant.

Now mechanical pencils are so cheap you're best to buy dozen packs (because although they last forever you will lose them now and then), and the leads can be bought cheap in very large quantities via Aliexpress and such. Don't buy leads in the tiny. expensive packs from local stationers.