SAFD: Being 100% honest, wearing costumes was a giant part of what made me want to try runDisney in the first place! So yes, I will always take the opportunity to dress up.
The longer the race, the more strict I am about tech materials and being close to running clothes. But for a 5K or even a 10K, I'll go full out with a costume, including wigs, props, etc. I also lean toward things that look good in the dark or that I can light up, since those are mostly run in the dark.
I've moved away from super elaborate themes as I find most people just don't get it, and then I'm disappointed. My last Dopey, I did a series of Inside Out characters mashed up with the race theme character (ie Anger/Donald for the Half) and I even switched costumes mid-marathon (Disgust to Joy). It was really fun to plan and do, but even with my custom shirts that explained it, I'm not sure most people got it.
For this Dopey I'm going much simpler. Not sure yet what the 5K will be, but I'll reuse something I've run in before. I'll join in the
group costumes for the 10K (CM Flag shirt) and Half (working on the rainforest floral-spotted panther, with simple color-blocked running skirt and tshirt).
I know I JUST said simpler, but my marathon costume requires a bit of context. I was born in KC and am a HUGE Chiefs fan, so we're usually in the playoffs during MW. I've always wanted to do a Chiefs costume, so I'm finally doing one, but as a nod to the haters I'm mashing up a Patrick Mahomes tech material lightweight jersey with a Kermit green running skirt. I'll add a Kermit green visor with some patches representing Muppets and Chiefs, and add some felt Kermit eyeballs. (Mahomes sounds a lot like Kermit, and rival teams like to poke fun, but he takes it in stride.) So while this may still be a bit of an inside joke, at the very least I can rep my team.
I second all advice to TEST RUN everything! I have most of my costume pieces but am still waiting for a few to arrive. I tend to order from the same stores or Etsy shops so I know what to expect with materials. I tend to assume/buy for hot weather, and I have lots of generic leggings, arm sleeves, gloves and headbands for potential cold weather.
A couple of tips from someone who has run in Tink wings a few times:
1. Be aware the width or depth the wings may add to your body and be VERY aware of people around you. I'm a short, small person and it was tough to keep my wings out of people's way in the corrals.
2. Even if they attach with straps, pin them to your shirt or sports bra. Definitely do a test run with them secured different ways. I found the straps would slide at the adjustment point during my run, making them loose and causing the straps to move and chafe. I pinned them to the back of my shirt but also pinned the straps to themselves so they couldn't slide.