The last time I set up DNS at home, I decided to use a fictitious and undelegated subdomain under my ISP's domain name. This structure did not create any "extra" problems in the short term.
But I suppose that I still ran the risk that the subdomain could "become real", or draw attention from security admins, or I would change ISPs.
But I suppose that I still ran the risk that the subdomain could "become real", or draw attention from security admins, or I would change ISPs.