Rachel Bilson's Must Haves: From a Flavored Lip Balm to a Jalapeño Tequila

As for the one essential she "can't be without," Bilson swears by this plush Coop The Original Adjustable Pillow ($75). "When I travel, I bring my Coop Original Adjustable Pillow with me — even on an airplane," she says. Unlike other pillows, this product is made from a memory foam and microfiber blend which is designed to provide ample support for the head and neck — plus, it's easily adjustable, so you can contour it to better fit your sleeping preferences.

Pro Tip: To help preserve the pillow's freshness — especially when she brings it along as a personal carry-on item — Bilson likes to cover it with two pillowcases as opposed to just one, that way she can "remove the dirty one" once she arrives at her destination. Genius.