Do you have to update the address each time you update your homepage?

Yes. There are some alternatives and frameworks like Fleek that abstract this away from you but the most straightforward way is to update the CID with each update.

Fleek can point the ENS name to an IPNS entry which retains the decentralization, keeps UX simple for years, and eliminates gas fees for updates. https://blog.fleek.co/posts/ens-now-on-ipns-hash-updates