After my first year gardening, I label everything, because otherwise I have no idea what's what.
Well, unless I'm running out of time and seedlings are dying in their little cells. Then, sometimes, the stragglers in each tray get thrown into the ground willy-nilly where there's room left - with my best wishes, but not always much hope for survival.
Even then, I do label the biggest and healthiest ones, well-spaced in the better beds, hoping that I can find some markers near some surviving plants, discover what they look like at that growth stage, and then also recognize unlabelled specimens of the same variety planted elsewhere.
I use mini-blind slats and pencils. When starting seeds in a propagation tray, there will be many more transplants than labels, and I tend to run out in the garden, while transplanting. Starting with 6-packs, I'll make a few extra before going outside so I have enough labels to mark at least every second or third plant.
Potted-up plants are easiest, becuase then I already have one label per plant.
I never considered using extra-hard lead to resist smearing! Instead, I usually use medium-soft lead (HB) to get a darker mark.
I like the 0.7 mm mechanical pencils, becuase they're "always sharp", yet the mark is wide enough to be dark. My handwriting is so bad that it's illegible if the mark is broad or wide.
