I find that regularly applying lip balm stops my lips from going dry. I seriously apply it about every half hour though, I'm addicted to lip balm.
The only time they have been dry recently is when I was ill. And my lip scrub sorted that right out when I was better.
Try to avoid petroleum based lip balms (including vaseline). Not everyone will agree but I find that they make my lips drier. And you know what I've found recently, I used to love Carmex but I haven't used it since I switched to making my own. Well anyway, I bought some recently when I ran out of my homemade stuff and it tastes freaking disgusting and it feels horrible!! Vaseline is the same. I was so glad to get some time this weekend to make some more of my own.