I have some leggings and a long sleeve top that are priceless to me. I use them all the time...namely to regulate my temperature in colder conditions.
Whether I'm running outside at 3am or working on set, in the cold...this pair keeps me warm, comfortable and flexible.
I think I bought it to keep me warm while filming outside, in the freezing cold. It's worked.
Not to mention, I can wear them under my clothes, as well.
Worth it? Yes!