You may never be fully dressed without a smile — but the right undergarments don't hurt, either!

And, according to our guest, expert bra fitter Kimmay Caldwell, there are three bras your bra drawer is desperately missing.

The first? (Which was modeled by our viewer, Vanessa.) A contour bra with memory foam, which conforms to your unique body shape. (The example bra, the Gorgeous Memory Foam Bra from Paramour by Felina, starts molding soon as it hits your warm skin.)

The second must-have is a convertible bra — a.k.a. a bra with two (or more!) straps that can be snapped and un-snapped to your liking. This way, you never have to leave the house with your straps showing! (Rachel Kara is wearing Le Mystere's The Perfect 10 Bra, which comes with a lace overlay and straps that can be worn 10 different ways!)

Finally, Kimmay revealed one of the newest bras on the market: a sports bra with perforated, ventilated cups made from moisture-wicking material. Kimmay says this breathable bra — Warner's Play It Cool bra — is is good for everything from hot yoga to hot flashes. (Woot!)

For more tips from Kimmay — including the five bras every woman needs for day-to-day life — watch the video above!