A $685 plane ticket for the bachelorette party? A $1,000 deposit to rent a country club for the bridal shower? Just when you thought the cost of wedding gifts and attending destination weddings for the Bridezilla set couldn’t be more ridiculous, here comes the bridesmaid. Standing up beside your BFF on the big day can cost the big bucks and so can sitting down next to her at all the tea rooms, bars and beach houses that can play a part in the days leading up to it.

To be fair, this is not true in every situation. There are cases where a bride and groom are both very reasonable with demands on their attendants’ bank accounts. Some even offer to foot the bill for at least some of the expense if they’re in a higher income bracket than their chosen bridesmaid or groomsman. But other engaged couples seem oblivious to the unfair burden their desire for, say, two separate tailored gowns or a destination engagement party can place on their nearest and dearest. How much is too much? Whether you’re anticipating an invite to become a bridesmaid or just want to shock yourself about the spending habits of the rich and newly engaged, check out these factors that determine what it actually costs to be a bridesmaid:

How many events you’ll be involved in

A May 2017 study from the Wedding Wire website found bridesmaids spend $1,200 on average per wedding, though some spent literally thousands more. The factor that heaped on the most additional costs were for travel and event-related expenses that make up the whirlwind multi-month celebration. This could include plane fare and lodging for destination bachelorette parties and multiple showers (or just one somewhere expensive.)

Not every bride opts for all these soirees. Nor does every bridesmaid have to attend them all, especially if she lives a plane trip away or the whole group is traveling somewhere else not within her budget. But top experts urge potential bridesmaids to share such misgivings early on. That way, the bride can adjust her expectations or you can agree she’ll select someone else to take on the role if you can’t make enough of the pre-wedding festivities to suit her.

How much control the bride wants over the gowns

Besides being a standard joke and something that may end up never exiting the closet after the nuptials, a bridesmaid dress can cost in the hundreds or more. There’s a nice trend where some brides just choose a color and let all the bridesmaids choose a style that they like. This is the best-case scenario budget-wise since a bridesmaid can then shop for bargain dresses using an app like ShopStyle that alerts you to price reductions on gowns you’ve viewed. Careful shopping for a dress that only needs to suit an individual bridesmaid can cut the cost below $100. Borrowing is also an option at this point. The “choose your own style” approach also may eliminate some of the costs for alterations (which can exceed $50-$100) and new undergarments if the bride’s chosen fashion is strapless or some other high-maintenance style.

Another cost that comes in when the bride wants to choose the specific dresses: Shoes. It can be pricey to buy the same shoes as the other bridesmaid or have a pair you already own dyed to match. Happily, if your bride-to-be is up on her etiquette, she’ll realize she’s responsible for paying if she wants all her attendants to wear a certain accessory. That could be anything from a sash to a brooch to a headband.

Whether you’re the maid of honor

The maid of honor is usually the bride’s best friend, but even she may be surprised at what she’s expected to pay for. Along with a special dress, she’s usually in charge of planning a shower, which could include unexpected expenses like the decor or deposits for any venue or equipment rentals.

Whether the bride is easy-going about professional styling

This is your friend, but if you haven’t seen her for years, you might be surprised at her expectations of your appearance on her big day. The bride may insist that everyone pay to have their hair done professionally and ditto on the make-up. This can cost in the hundreds of dollars. There may be some squirm room. If you’re comfortable asking, the bride may happily agree to you doing your own make-up and saving the 100 bucks it can cost. The best a bridesmaid can hope for is that it’s not specified so you can make your own plans.

How fast the hidden costs add up

There is just no telling what sort of expense might crop up in the months a bridesmaid spends fulfilling her role to the utmost. Suddenly, everyone is wearing matching sashes to the pub crawl for the bachelorette: $9. You are informed you need to pay “your share” for the screen-printed bridal shower/cookout koozies: $35. With one month to go, the bride casually mentions it would be great if all the bridesmaids were able to change into short gowns for the reception: $138. The list goes on and on.

Here’s where assertiveness really pays off. For any expenses that are clear from the outset, a potential bridesmaid should draw up a list of expenditures and a matching savings plan. If it doesn’t look realistic, it’s time to talk to the fiances about what you can afford. Make sure to give them the option of finding someone else to be an attendant so you won’t stand in the way of whatever scale of wedding they have planned. A rule of thumb is never to go into debt to be a bridesmaid. And the corollary: If you can’t live up to the bride’s expectations on your budget, it’s only fair to decline the honor and salvage the friendship.