There are no set times on when you need to rewire your property. Just because wiring is old, does not mean you need a new one. We would advise you to do a periodic inspection every 10 years and the test will certify whether the electrics in a property are safe and tell you if anything needs upgrading.
When hiring an electrician in Singapore, it's important to look for someone who is licensed by the Energy Market Authority (EMA). The EMA is the regulatory body in charge of overseeing the electrical industry in Singapore and ensures that electricians meet the required standards for safety and competence. Electricians are required to obtain an EMA license before they can carry out any electrical work in Singapore. You can check the EMA's website to verify the license of an electrician
Regular maintenance and inspections can help to ensure that your electrical system is safe and up-to-code. This includes checking for loose connections, frayed wires, and other potential hazards. It is also important to make sure that your electrical system is properly grounded and that all outlets are grounded and polarized. If you have an older home, it may be a good idea to have an electrician inspect your electrical system to make sure that it is up-to-code and safe.