How do I build things that last beyond me?

You engineer for people you will never meet, who will depend on your work long after you are gone. That is a rare thing to hold clearly, and it changes what good work means. You are not just solving today's problem; you are leaving something behind that others will stand on, or stumble over, for years. Building to last is partly craft and partly humility. The craft is in doing the work soundly, clearly, so the next person can understand and maintain it. The humility is in knowing you will not be there to explain it or fix it, so it has to hold up without you. Work built this way is a kind of gift to strangers, quiet and lasting. So build as if you will hand it off tomorrow. Ask whether someone who has never met you could pick this up and trust it, and where the answer is no, make it clearer or sounder. You will be gone from it long before it is gone from the world. Leaving it solid is how a small part of your care outlives you.