The answer is YES! Planning the entire wedding without a planner/coordinator is already stressful enough, so the least you can do is hire someone who can handle the stresses of the day. Your peace of mind on your wedding day will be worth every penny!
You want to party amongst your guests and look radiant, not scramble when a vendor runs late or hunt down a bridesmaid who goes missing seconds before the wedding march begins to play.
A lot of Brides say "I'll just have my MOH handle it or my BM, but there are so many things that can go wrong during or before a wedding that an untrained individual wouldn't know how to handle - For instance if your baker brings the wrong cake, your Best Man probably wouldn't even realize it, he's never even seen the cake before today or do you really want your Maid of Honor setting up your reception tables or your sweetheart and cake table when she's supposed to be getting her hair and make up done?
A Day of Coordinator takes the planning you've already done and execute it as you become consumed by things like enjoying your family and being photographed looking pretty. They will create a timeline, set-up your ceremony and reception, keep you on schedule, manage your vendors, cue your services, and much much more!