Like other responders, I question your statement "...I might not be as effective as I once was.".

Judgement based on long experience can be enormously valuable. You may see in your client's current circumstances a dynamic you worked through 30 years ago. As a result, you may save your client a month or two exploring solutions you know won't work for them.

That's incredibly valuable. Consider that when pricing your services.

But how do you sell judgement? People don't want to hear, "That won't work" type of advice. The culture rewards "I can do the impossible" overconfidence. When you find out the project is harder than you thought, you just work nights and weekends to make up for it because you have no spouse or kids to neglect. (Yeah I've used that advantage myself when I was in my 20's.)

Put yourself in situations where "I can do the impossible" overconfidence leads to running up against the brick wall of the impossible and having to start over. Usually that means some form of consulting. A lot of older developers have a lot of luck specializing in fixing problems that have previously been fucked up by junior developers, often using older more-stable technologies or working in tricky problem domains where there are a lot of gotchas.

Don't undersell your experience. You might not realise it, but occasionally an insight to use a particular approach might shave days to weeks off the development timescale.

It's not all about how fast you can hammer out bits and bytes.

"Weeks of programming can save hours of planning."

This is where experience really counts. Younger developers who don't know any better will invent another logging framework, I guarantee it.

Haha, I did this (created another logging framework) at 23. It was a plugin-driven Python framework and it was beautiful (at the time), but was it necessary? Most probably, certainly not. Ah but I loved writing it. Really made me a better coder.

Are you really less effective? I would assume that experience would be a big help in making a developer more effective? Or are you saying you may be as effective, but not as able to work the crazy hours that still seem to be far too common in the industry?

Yeah I get a lot more done in a shorter amount of time at 42 than 19, but the 20 hour days are really punishing, although offset by being able to work some of it remote, but for companies that chart success by sheer number of hours and face time clocked rather than projects completed these are in general a poor match for any effective developer.

I'm 29, and I have already started feeling this. Just a few years ago, I could do 12-14h coding days sustainably, but now, anything above 11h sustained for weeks really shows in my output quality. Luckily, my overall productivity is still rising due to learning and experience, despite the degrading mental capabilities. I don't know what me at 35 will look like. I now see where the ageism comes from.

I find it incredibly sad that I even need to think about this. I regret that I even participated in this circus in the first place. I now only work for companies with don't have the ass-in-seats-for-80h policy. It's actually interesting that in startups where this works, people self-select and end up there. It's amazing how much more you can achieve if you can afford to take a step back, and not worry how you can run in circles even farther and faster.

Don't work 20 hrs; that's 8hrs productive, 6 hrs at 50% and 6hrs probably making a big mess. Followed with 8hrs at 50 % and 12hrs making a big mess.

Have the courage to stop, sleep, eat and then come back with a fresh mind.

This. I am willing to work fewer hours a week now. For most of my career, I set a maximum of 32 hours a week to work (not counting writing activities). I now work much less than that.

There is a lot of value in having someone who is always available. That is not me since I work in spurts, with long breaks. I think lack of always on, immediate availability is important for some projects, and I am unwilling to do that.

With age you can become more effective! As a 64 year old Developer I tell clients that my USP is 'grey hair'. Younger developers may produce slicker code and better SQL structures - but having run businesses I can look at the requirements from a Directors/Owners point of view and guide them on how to get the most benefit for their organisation from the technology.

Not to mention avoiding organizational problems that younger developers will blithely lead them into?

Youngsters these days can't do SQL. Its all MongoDB and Node.

That's rubbish. I'm young and know SQL fairly well, it's still a very valuable skill. If you base your opinions of young developers on HN articles then that's your problem.

Mark, I think you're undercharging. May I ask you, have you tried higher rates and had problems with finding clients? i.e. how did you arrive on your current rates...

Well, I do charge a good rate when I work on site. Also, sometimes people pay more than what I advertise if they want a lot of time and instant availability. In general, customers who are willing to work around my life style get a low rate. This seems fair.