This is by no means the ONLY way to set up a budget. It's just how I do it. I've played around with a bunch of budgets over the years and this seems to be the best method for us.
I set up a budget for every pay period. There are a few reasons why I do this: (a) I can look at the calendar and see potential money traps (i.e. birthday parties, date nights, etc.) a lot easier if there are only two weeks to look at (b) If something unexpected comes up (like tires or medical expenses) then it doesn't ruin my entire budget for the month and (c) because I'm a micromanager like that.
So each pay period, I open up my excel spreadsheet and enter my figures.
My next task is to calculate how much we overspent the pay period before (column I). Obviously, most of our expenses are set amounts every month, but there's a lot of room for overspending in groceries, gasoline, and miscellaneous.
At the end of the two pay periods for that month, I then calculate the amount we overspent in those key areas, slap my wrists and go on to the next month.
Over time, I have found that if I *see* how much we've overspent the previous month, I'm a little more mindful of what I'm spending in the future.
I use Quicken to put in all our transactions. This connects automatically to my bank account and downloads the information so I don't even have to enter it in by hand. Very smooth. While it has a lot of cool features on it to do budgets and savings goals and what not, it's a little busy on the screen, hence the excel spreadsheet.
So here's my advice:
Set up a budget however you think your family will benefit the most. Some people have one check a month designated for mandatory expenses (mortgage, cars, utilities, etc.) and the other check for discretionary expenses. Some are only paid once a month which has it's pros and cons. Whatever works for you, set it up.
Next, follow it religiously for the first couple of months, checking in a couple times a week at least, to see if you're still on track.
As you get into your groove, you'll eventually get to where you don't have to check your budget every day to make sure you're still on target.
Re-evaluate your budget every quarter to make sure that it's doing what you want it to do for your finances.

