If you don't pay for it, you have to stay on top of it to keep it alive. I hit mine every Sunday. Making it a habit that way helps.
If you don't trust Hush, get a copy of GPG and learn to use it -- Hushmail is in many ways a crutch.
But most of all, don't ever forget that a chain is only as strong as the weakest link, and you are at the mercy of the worst in every person you deal with. You can be betrayed by greed, cowardice, laziness, or stupidity, singly or in combination.
You can also be burned by someone who thinks he's "doing the right thing," which is often worse.