As the OP for this thread I will say that there is no specific time or day of the week when the subject changes. I think it's generally about 3 - 5 days on average. The 'clouds' subject started this past Sunday so it fits the overall pattern. I understand about gathering particular photos; I do it too and am sometimes surprised to open the thread and see that the subject has changed and my selected photo no longer fits.Is there a specific time period or day of the week when the subject changes or is it spontaneous? I spend a lot of time looking through my photos for each subject and then when the subject changes suddenly I feel unprepared (or over-prepared for some I guess). If it’s spontaneous, I will just gather fewer photos at a time. Thanks!