I've been billing daily but yeah, in my limited consulting experience hourly is way more stressful and it isn't practical to have to account for your work at that level of granularity. Especially since this is a question specifically about long term work.
That being said, this question is more useful as an hourly rate since some people set their daily/weekly rate different because they work more or less than an 8 hour day / 40 hour week.