...don't do it. Keep your attendants to five or fewer on each side.
1. BUDGET: For every BM or GM you add, you pony up for another plate at the RD (more if they have SOs), another bouquet/bout (not cheap), another gift, another round of hair and makeup, another plate at the bridal luncheon (if you're having one), and an even bigger head table (which is usually more decorated than other tables).
Plus, say you find a great deal on shoes, and snap them up for $40 a pair and ask the BM's to pay you back. With three girls, you're out $120 and have a few people to track down. With eight? You're out $320, and if they don't pay you back right away you're eating ramen for a month.
2. WEDDING PARTY BLOAT: I'm not talking about the sodium from all that ramen you've been eating. I'm talking about, "Well, if I asked Sleepy, I should ask Dopey, and if I ask Dopey, I should ask Doc." Before you know it, all seven dwarves are prancing down the aisle to Canon in D. (more)