Cooking carries on after the pan is off, so move the eggs to a bowl of cold or iced water as soon as the alarm sounds. This stops the cooking, helps the yolk stay the colour you intended and makes the eggs easier to handle. Older eggs generally peel more easily than very fresh ones, and tapping the shell all over before peeling can help.
For safety, cook eggs until the whites are set. Pregnant people, young children, older adults and anyone with a weakened immune system are usually advised to eat eggs cooked firm, with no runny yolk, so choose Firm, Hard-boiled or Extra firm for them. Follow your local food safety guidance, as advice differs between countries.
If you plan to keep boiled eggs, cool them quickly and store them in the refrigerator, and use local guidance on how long they stay good. A few hard-boiled eggs make a useful stock for lunches and salads, and doing them in one batch with a single timer saves energy and attention. Label the box with the date, and remember that the shell protects the egg, so peel only what you are about to eat.
The timer measures time only and does not know the state of your egg. It also needs the page open to ring, and a phone that locks its screen may stay silent, so keep a second alarm nearby. For a different length, such as a ten-minute simmer for a larger batch, you can use the 10 minute timer or change the boxes. The countdown timer has the same controls without the egg presets.