Last night I worked until 5AM on a magazine article. Upon review the later stages of my work weren’t of my usual quality level, and today I did nothing significant because I was too tired (fortunately it’s a Saturday).
I’m now going to cease all really late-night work except when supporting 24*7 production systems for clients. When I feel that my productivity starts to slip due to being over-tired I’ll cease work unless I am being paid to get an outage fixed quickly. The real problem in productivity seems to be throughput not response time. So if I occasionally miss a deadline but overall get more work done it should be a net positive thing.