suggestion: March 27th, in honor of the x86 processor, and also because it's coming up soon
march 26th in leap years
what is the significance of 27th of march re x86? I thought maybe the release date of 8086 but that looks to be 8th of june 1978
I change them when I change smoke detector batteries: the weekend after the Daylight Savings flip in winter
January 28, May 12, and October 24 would all be good candidates! In fact we could do all of them and make it the Triannual Preventative Maintenance days where you blow out the dust and check wear and tear items.
(the jokes: 1/28, 5/12, 10/24 are Funny Computer Numbers. TPM is a kind of security coprocessor.)