Ask HN: I'm 40 and feel my mental ability declining. Programming seems harder.

Great advice, I was going to suggest the same. You shouldn't have to memorize what each layer of a project does, that's what the unit tests and integration tests are supposed to prove.

I'm a little bit older than you and have been in the industry for almost 30 years. I have a different perspective than mental decline. I think it's that after seeing code and patterns for so long, you might be defaulting to generalization of ideas. I know that I do that.

For example, one of the best developers on my team (a little bit older than me) is "on the spectrum". We've worked together for nearly 20 years, starting at about the same time. Early in our career, we would dig into the details of APIs and patterns and be able to rattle off the details of the changes when a new dot release of an library came out.

As the years have gone on, I've "lost interest" in the details knowing that I can look them up when I need to and have naturally defaulted to generalizing ideas. That is, rather than knowing that we need to change the third parameter in the function call in FOOBAR 3.2 when we upgrade from FOOBAR 2.9 because the details of the memory management changed, I just know that we use the FOOBAR function because it does a specific task that we need.

The reason I bring up my friend/coworker is that he never generalizes, he gets stuck in the details. He can't design his way out of a paper bag, but he can write thousands of lines of code over the weekend with full unit tests and there's never any bugs. So we make a great team, he's one that has focused and has every detail at the tip of his tongue. But he never sees the big picture.

So I view getting older in software as (over) training AI. My brain works in the generalization route and the more I see, the more connections I make, but I need to "make room" in my brain by not encoding the details. My friend's brain works differently. He encodes details and can keep a deep call stack but at the expense of ever being able to see the big picture.

I guess that's a long way of saying that maybe you shouldn't be so quick to think it's cognitive decline. It could be just that your brain is encoding things differently after seeing so many examples in your career.

I know I'd fail miserably at porting an API now (I've done that when I was younger very efficiently). But I also know that I can bring a much higher level of design and ideas to the team than I could have 20 years ago.

IDE code intelligence can help a lot. Anything that makes reduces the cognitive load of navigating within the codebase helps increase the mental capacity you have to keep the context loaded.

When tracing deep call stacks I can find it helpful to write out the question I am looking for the answer to in a comment. Then I can retrace my thoughts back up the callstack using the very handy shortcut to go back to the previous curson position.

This is good advice. Just a few days ago I randomly stumbled upon a youtube video where someone was using — blast from the past, here — a hunk of green bar line printer paper as a big scratch pad to write on. It made me wonder how I ever got out of that habit. That stuff, when it was ubiquitous, was the best scratch paper ever, and I used to do it all the time when I was young and, one would think, at my cognitive peak. Maybe falling out of that habit is part of my percieved decline.

I’ve felt this too in my 40s. I generally don’t recommend books that might be considered self-help, but a recent book by Arthur Brooks called “From Strength to Strength” was really helpful for me to understand what’s happening to me, and how to embrace the use of crystallized intelligence in my later career. If that doesn’t interest you, you can find some interviews with him about the subject and book in a few places by search.