Earlier, people who had diabetes were monitored mainly for the amount of sugar in the blood when they got up in the morning, before they'd eaten. But this gave little or no picture of the fluctuating levels during the day. This can level out to one or two tests at different times of the day. Until the person can know their body's tendencies and formulate a plan of action, more frequent self-testing may be advisable. This entails learning to use a lancet on the side of a fingertip.
Modern lancets have a trigger device that sends a sterile needle just through the skin.
I've learned to do it without wincing, but I refuse to enjoy it. Like magic, one drop of blood placed on a high-tech paper strip, inserted into the monitor, brings signs of computer cogitation to the monitor's little screen. That develops into a number that tells me whether I'm in good control. So far, it still badgers me to do better. Ideally, folks with diabetes work with a dietitian to help plan meals according to likes and dislikes, and considering blood sugar levels when certain foods, or quantities of foods, are consumed.