Ask HN: I'm 40 and feel my mental ability declining. Programming seems harder.
I don't know you personally but I doubt cognitive decline has anything to do with this.As we age, we usually end up with more and more life responsibilities, beyond just the work we are doing. All of that is input to the brain and requires energy in response. The brain is not infinite.I often feel as you do, but then I have periods where I am as light and agile in my productivity as 20 years ago, maybe even more so, and usually it is my life circumstances that are the culprit.I remember once about 13 years ago I was working on a mobile game and had a similar problem as you describe; there was one day where the technical work seemed to overwhelm me and I felt inadequate. But I was just a young chap, and it was a passing moment -- I had indeed just taken on some enormous new life responsibilities at that time, which were the likely explanation.Burnout is real, too, and giving yourself space (if you can) to relax and not think about work for a break can be quite useful to recharge.