The answer to 'what size rewiring do I need' is that the size of rewiring needed for your home depends on several factors, including the size of your home, the electrical load requirements, and the current wiring setup. As a general rule, most homes will require 100-200 amp electrical service to accommodate modern electrical needs.
When rewiring a home, it's important to work with a licensed and experienced electrician who can assess your specific needs and recommend the appropriate wire size and electrical panel capacity. They will also ensure the rewiring is done safely and up to local electrical codes.