I will register all of my domains for a 50 year term. This will assure and guarantee that I will have my domains for the rest of my life. If for some reason I should live to be more than 100 years old, I will continue to renew the domains, and if I have the resources, I will register for another 50 years.
Almost all of my domains are my personal domains, and will have multiple sites. When possible, I like to keep the number of domains to a minimum, and rely on sub-domains when a site isn’t too significant. If a subject requires multiple sites, then a domain will be acquired. There are a few domains that would always be in my inventory no matter what I would have in the future. Since these domains will be leased for a 50 year term, I shouldn’t have to worry about them for a long while.
Since the most likely instance of having a family will be fostering children, I will acquire a domain that I and the foster children will be able to use. As long as the foster child lives with me, they will have an IMAP based email address that they will be able to use their devices to log in, and check their mail. When they no longer live with me, their address will forward to their new address for 1 year. This will assure that everyone that writes to the foster child will be able to recognize the change of email address.
Since I am over 50, a 50 year acquisition of my domains will allow me to be older than 100 before I will have to worry about the domains. It would be possible that I will be deceased by then, and the person that received my inherited businesses will be able to deal with the registration unless they sold my businesses, or run them into the ground. As mentioned, if I am still alive when the domains will be due, then I will acquire another 50 year term.