I don't, when my son was little I had a Halloween party for him and his friends every year, it was a super big production and we had lots of fun but even for that party all I did was put on a bat headband or a witches hat. I typically don't like to dress up but it's fun for the kids!
I don't dress up unless my husband and I are going to a party. Last party I went to I was hugely pregnant. That was fun...Not only finding a costume but finding one that fit over my baby bump. I guess the trauma caused me to not dress up since 2004!