Lots of good suggestions!
OP, rather than downloading your spending into Quicken, try entering each receipt individually, into specific categories, at least weekly. Initially, be very specific. Break clothing into sub-categories by person, listing reason for each person (special occasion, back to school, summer, etc.).
It's work and can be a royal pain in the backside, but you'll learn how you are spending your money after a month or two. After that, you can use broader categories (i.e., "Clothing" with the description "Target-DD15 swimsuit). Break dining into TS and QS categories, just as you would at WDW. Groceries into food, beverages, household (laundry, cleaning products), vehicle care, personal care, etc. Pets? List by dog, cat, gerbil, with food, litter, toys, vet, etc. foreach. One of my colleagues has a lot of pets--she rescues cats and two of her dogs were rescues--and she didn't realize how much she spent on them in a year. That doesn't mean she will change, just that she now understands where a good chunk of her earnings go! *LOL* Just estimate the sales tax on each entry, tacking the balance onto the last item. Depending on where a I shop, sales tax ranges from 9.3% to 9.6%, so I round it to 10% on non-food items, with the last item picking up the slack, unless it exceeds 10% significantly. There are limits what I'll do to track my spending!
Then you need to have a meeting with your DH (don't include the young ones yet) to determine your monthly income and fixed expenses (housing, utilities, transportation, health insurance) and develop a budget for the remainder. Once the two of you decide that, bring the young ones in on the plan. Everyone has to be on board. In fact, your three older children can be involved in tracking the monthly expenses, and the younger ones can help by putting the receipts in the envelopes.
I've always followed something similar to the Dave Ramsey plan--long before Dave Ramsey! Smaller family and manual system prior to personal computers, so it was a more simplified system. But he has good ideas. If you know in advance where every dollar will be spent/saved/invested, you can deviate from the plan in an emergency and still be in good financial shape. And if your young ones--and you and your DH--actually use cash for a month or two for your purchases, rather than credit or debit cards, you will feel much more attached to the cash than the plastic. It's really strange how that works!
If everyone in your family is committed to changing, you're going to enjoy the ensuing freedom. And don't worry if anyone slips up a little occasionally--it's a learning experience, as well as a lifestyle change.
You're going to do fine!
