So we know that quantum computers hold a real risk of being able to break a lot of encryption. We also know that changing cyphers is hard (because reasons)

But what I don't see is what I can practically do now, as either someone who is a CTO/Big Cheese™ or a lowly engineer?

Perfect.

I have been hearing about one more technical hurdle to solve before quantum algorithms become feasible since before I graduated. That was in 1996.

I thought it was a typo at first but wikipedia explained:

The Sword of Damocles is an ancient Greek moral anecdote, an allusion to the imminent and ever-present peril faced by those in positions of power.

Shor's algorithm is a quantum algorithm for finding the prime factors of an integer

> if quantum computers start breaking cryptography a few years from now, don’t you dare come to this blog and tell me that I failed to warn you. This post is your warning.

What is the biggest number factored using Shor's algorithm?

Last time I looked it was very unimpressive.