The first of the month is when I (a) flea treat the critters (b) pay my car insurance premium (though it's done by automatic debit so it's not so much that I do it as I have to remember that it will happen so the funds are where they are supposed to be) and (c) take all my measurements. Results are pretty much where they should be this month, which is nice, though my menstrual cycle is messing with my waist measurement shrinking as nicely as the rest.
Oh, well, one reason I went with the calendar month for taking measurements is so menstrual effects will get averaged out over time and it's early days, yet.
Nice not to have rent to pay, that's for sure! Yes, still have the mortgage, but I've got that set up to be automatically paid as often as money comes in in the form of DH's paycheck, so it's relatively painless.