Day 64 on my counter. Slept in this morning and realized that this was day "100" base 8. Which got me thinking about what the natural numerical base for tallying things here ought to be. Maybe base 7. I seem to have "peaks" in attraction to my camera model about once a month, or about every four to five weeks, or "40" to "50" days base 7. The 90 day standard reboot cycle is close to 91 days, which is 13 weeks. Add another week and we're at 98 days , or "200" base 7 days. I like this. Today is Day "121" base 7, which I'll denote "Day 121_7" in my journal.
I would think that there are only 3 bases that would make sense for counting something on a day by day basis. Obviously there is decimal which would be normal counting. Base 7 as you mentioned which would be useful for counting weeks. And then base 60 which almost exactly cooresponds to 2 month incriments and also is a very mathematically nice base.