Whether it’s a wedding, a family reunion or your church’s Easter festival, big events cost money. You don’t want to base your decision on price alone, though, according to Katie Wilgus of Gather Event Planning. It’s important, for instance, that your vendors can deliver the level of quality and fit the type of event that you have in mind.

Be Clear On What You Want

Before you draw up a budget, firm up your ideas for the event. If you want a black-tie dinner, it’s probably going to cost more than a church picnic for the same number of people.The details will affect what supplies you need to rent and what sort of caterer to hire. “Find a caterer that you feel would prepare a meal that hopefully matches your theme,” Wilgus says. “If you’re going to have a Mexican fiesta, find a caterer that specializes in that and ask them to create a proposal for you.”

Know Your Limits

If you have a set budget to work with, it’s simply a matter of finding the most you can buy with it. If you have more financial flexibility, you have more options, such as a larger guest list or fancier food. Financial software can help you by showing the effect on your budget of all the varied options. “Some people find it extremely useful,” Wilgus says. “If nothing else, start creating a spreadsheet so you can compare costs and track your spending.” List everything you’re going to need on the spreadsheet, then fill in costs as you get estimates from vendors.

Select the Guest List

The more people you invite, the more carefully you have to budget. Draw up a list of people you think absolutely must be invited, and then double that for potential “plus ones.” If you’re allowing children as well, add them to the potential attendees. If there’s a fixed limit, such as the size of the venue, you’ll have to cross off anyone over the maximum. “Bridal Guide” magazine recommends you divide attendees into an A-list and a B-list. Ask the B-listers only if some of the A-list turn you down. You can use the spreadsheet to track the total cost for different numbers of guests.

Selecting the Caterer

The two biggest expenses in event planning are first, the price of food and beverages; and second, the cost of renting tables, chairs, plates and so on. If you know you need food, drink, and rental dishes and utensils for 100, getting an estimate on those costs will help you set most of your budget. Wilgus says you can save a lot of time by finding a caterer who can work with rental companies for you. “That’s something they specialize in,” she says, “figuring how many plates people need.”

Do Some Comparison Shopping

If you find two or three caterers who can provide the kind of food you want, ask them for proposals. Wilgus says you should look at the service they’re offering for the price, too. She says you want a caterer who’ll have the event thoroughly staffed, so your guests don’t feel they’re being neglected. Once you have the proposals, plug them into your spreadsheet and see whether you need to adjust your budget somewhere else, for example by cutting the guest list. Wilgus says catering proposals can vary significantly in price but bids from rental companies usually vary very little.

Stick to Your Budget

If you’re tempted to go over budget — more guests, fancier food, a live band — look at what effect paying the bills will have on your bigger financial picture. You never want to spend so much that you’ll regret it later. Throwing around money can also distract from the purpose of the event, whether it’s a bat mitzvah party or a formal business dinner. Caterers and decorators may be happy to encourage you to spend more, so once you’ve reached your limit, resist.