At 37 I'm much faster at debugging today than I was at 27. And 10 years ago, I was consistently one of the fastest debuggers in a company of 15-20 programmers. Debugging's always been one of my strongest programming skills.
So debugging, no, definitely not. I can spot root-causes of bugs now even easier than I used to be able to.
And one of the big new skills is that I'm much more able to 'guess' where a bug is in someone else's totally new code-base than I previously was able to.
In fact, I also write code faster as I get the general gist of it done much faster first time.
Some people specialize, and get more and more efficient at the same specific tasks; but I believe it's more common to widen one's experience in various areas (languages, tools, platforms, non-functional requirements etc.), leading to some lack of practice in the hands-on tasks one used to do everyday in the past, and also making it more difficult to commit everything to memory. On the other hand, one generally gets a much broader picture.
For instance, I used to be able to perftune UNIX and DB (mostly Oracle on Solaris) pretty well, knowing various kernel parameters by heart and all the tools of the day (tkprof, Cockroft and co). Now I guess I could still get by after some brush-up, but I'm not anywhere near as efficient as I used to be on that specific task. And I still write code, but I don't know every single method of every API anymore. But now, I can design full solutions, from choosing the hardware to setting up platform, languages, monitoring, high-availability, backups, security etc. Not because I'm smarter, but because I've been exposed to all that along the years.
So debugging, no, definitely not. I can spot root-causes of bugs now even easier than I used to be able to.
And one of the big new skills is that I'm much more able to 'guess' where a bug is in someone else's totally new code-base than I previously was able to.
In fact, I also write code faster as I get the general gist of it done much faster first time.