Originally posted by Kunyomi:

So I haven't played since before the Hearth and Home update and read it's best to start a new world to experience the new update fully.
Will there be another such update soon, such that I'd have to once again start a new world to have access to all new stuff?

Id honestly wait for at least this mountain/cave update.

It should be coming out really soon, as it is already in a public test branch on steam.

This upcoming update could break old game saves that people have and I think the new extra content and tweaks to gameplay mixed with Hearth & Home will be enough to make the game feel fresh again.