[mattm]

What is a typical day for you? You are a founder so I assume your day is broken up into many different roles. This is very different from a programmer or writer who is focused on doing basically one thing for his whole work day. Do you have any health issues?

> Frequently enough I've put in sustained 12-16 hour days for weeks on end to meet a tough deadline

I think many of us have done this here. What I've noticed from doing this is I start to make lots of mistakes that I wouldn't normally. At a certain point, this turns into a vicious cycle where I think slower and make more mistakes so I need to work more to fix them.

Maybe you're superman and can really work all those extra hours at full concentration...but probably not.

Here's an easy way you can check. Use a timer and throughout the day start the timer when you are going into work that requires full concentration and then stop it when you're done or someone interrupts you or you need to go to the bathroom or you break off from your task. Meetings and emails don't count.

I think you'll be surprised at the results.