I used to do it manually, then one time I went out of state and my IP address changed overnight. It was only by sheer stroke of dumb luck that an email alert was generated from my home PC, and I grabbed the originating IP from the email headers of the message. If not for that, I would have been out of luck until we got back into town.
So I signed up for a free DynDNS account for use at home.
I still use home-hostname.mydomain.com, but it's a CNAME to the Dyn address rather than an A record.