In my mind there's a difference between combining errands and putting something off/buying something in advance just so another day can be a NSD. I think that's why we don't have many. So I'm going to let it go, we have a budget so as long as we stick to that the rest doesn't really matter.
When the payslip arrives we have our budget meeting, lots of our costs are fixed so we don't need to look at them often, we account for any variable costs like birthdays or what have you then that's that. The money is given a name and that's all there is to it. Very occasionally there might be an emergency budget meeting part way through the month if belt tightening is required but in the main we write the budget then it tells us what to do.
If something is on special offer when we do spend we do one of two things, either bulk buy to tide us over until the next time it's on offer or we save the difference. That is fun saving when there's a bit of cash off and the saving can go into the Q box. Again, it's just a trick but it's something that works for me.