A follow-up, if I may: Given what you know about the math behind this: How confident do you feel having your entire Bitcoin wealth in a single wallet? (Assume you have perfect OPSEC and the only "risk" is an accidental or brute-force collision with your wallet address.) Just curious.
If my security, privacy, process of making transactions, etc., are all perfect (they aren't, and neither is anybody else's), then I would be completely happy having all my funds in a single wallet. The risk of an accidental or brute force collision is zero. While theoretically possible, even if the entire human race diverted all its power and resources to nothing but generating new bitcoin addresses until the death of our sun in ~5 billion years' time, we still wouldn't see an address collision.
Here's another way of thinking about this number:
Let's say we have a trillion planet Earths. On each Earth, there are a trillion people. Each person has a trillion computers. Each computer generates a trillion keys a second. All these computers have been creating a trillion keys per second since the birth of the universe 13.7 billion years ago. 10^12 * 10^12 * 10^12 * 10^12 * 60 * 60 * 24 * 365 * 13.7 * 10^9 = 4.3*10^65. This means thay they would have so far generated approximately 0.0000000004% of all private keys.
Having said all that, I absolutely would not recommend keeping all your coins in a single wallet. Not because I am in the least bit concerned about address collisions, but because nobody's OPSEC is perfect regardless of how hard you try or how good you think it is. Different wallets, different devices, different mediums, different back ups, and so on.