FI switches, also known as residual current devices (RCDs), have been mandatory in many countries for several decades. In the UK, for example, they have been required in new installations since 1981. The exact date of when FI switches became mandatory can vary by country and region, but the trend towards requiring them in electrical installations has been ongoing for many years due to their proven ability to prevent electric shock and fire hazards. **

Retirement is not mandatory in most countries. It is a personal choice based on individual circumstances, financial readiness, and personal preferences. Some people choose to continue working past the traditional retirement age for various reasons, such as staying active, pursuing a passion, or maintaining social connections. However, some professions or industries may have mandatory retirement ages due to safety concerns or physical demands. **

USK is not mandatory in Germany, but it is highly recommended for video games to be rated by the USK before being released in the country. The USK rating helps inform consumers about the content of the game and ensures that it is appropriate for certain age groups. While it is not legally required to have a USK rating, many retailers and platforms may choose not to sell or distribute games that have not been rated by the USK. **

In the United States, recess is not mandated at the federal level, but many states and school districts have policies in place that require a certain amount of recess time for students. However, the specifics of these policies can vary widely. Some schools may have mandatory recess periods, while others may leave it up to individual teachers or schools to decide how to incorporate breaks into the school day. Ultimately, the decision on whether recess is mandatory depends on the specific policies of the school or district. **

Confirmation is not mandatory in all situations. However, in some cases, confirmation may be required by an organization or individual to verify information or secure a reservation. It is always a good practice to confirm appointments, bookings, or important details to ensure accuracy and avoid any misunderstandings. **

No, fatherhood is not mandatory. While many people choose to become fathers and find fulfillment in that role, it is ultimately a personal decision. Some individuals may not feel ready or willing to take on the responsibilities of fatherhood, and that is completely valid. It is important for individuals to make their own choices about parenthood based on their own desires and circumstances. **

Vaccination requirements vary by country and region. In some places, certain vaccinations may be mandatory for children to attend school or for healthcare workers. However, in many places, vaccination is not mandatory but strongly recommended to protect individuals and communities from preventable diseases. It is important to check local regulations and guidelines regarding vaccination requirements. **

Excursions are not usually mandatory, but they are often encouraged as they provide valuable learning experiences and opportunities for students to engage with the subject matter in a real-world context. However, some schools or programs may have specific requirements for participation in certain excursions, so it's important to check with the school or program to understand their policies. Ultimately, excursions can enhance the overall educational experience, so it's generally beneficial for students to participate when possible. **