There's a great Lovelyish
post about traveling- what goes in your cosmetics bag when you can't bring it all with you. Because let's be real, if we could, we'd put our entire traincase full of everything into our suitcases and just be done with it. After all, you never know when you'll need your violeg MAC pigment.... actually, you probably should know that, haha. But the point is that you have to take things that you can't take every option you have "just in case". Keep it simple and everything will turn out just fine.
Most days I carry a little makeup bag with me in case I need something. It's pretty much guaranteed to take me from day to night or to help cover a blemish should one deign to appear or really, anything

So, here are some of my tips for traveling.... what to bring and what to leave.
Foundation: When I travel, I'm leaving the city which is a welcome thing indeed! And I know I won't wear foundation every day so instead of bringing the whole bottle, I'll pour a little into a little sample container that I have and
voila... I've beat the carry on restrictions and saved room in my bag
Powder: I have oily skin, so powder is pretty much a godsend and a way of life for me. I use MAC Select Sheer pressed powder in NC45 and it's truly wonderful stuff. It's the same color as my foundation and honestly won't change the shade of your foundation or skin tone. MAC asserts that it "blends lines" and it does... it truly finishes any look, but I always have it because it gets rid of the every-hour-oil-slicks which my skin just loooooves to show. I must apply this stuff at least 4 times a day and it never looks cakey or like I even have anything on! It's the most natural looking powder I've ever come across. If your skin isn't oily (lucky you!), you don't necessarily need this. Leave it at home... its day will come :)
Concealer: The foundation and powder together pretty much have my skin looking like what I wish I was born with. My eyes, however, are what I was born with: lovely inherited purplish permanent dark circles. Lovely. No matter if I've gotten 2 hours or 10 hours of sleep, my eyes always look like I'm battling a death sentence. To combat that, I use Bobbi Brown's Corrector concealer in 'dark peach'. For people with very dark circles, the darkness has to be neutralized first before a yellow-based shade can be applied. After the corrector is applied, I use a little of the foundation and powder to set and I'm done!
Eye Liner/Shadow: Keep it simple! It's unlikely you're going to have to do wake up at 3am so you won't be needing that I've-had-a billion-hours-of-sleep look, so leave the white/flesh toned pencil at home. Instead, bring a black pencil liner which can double as an eye shadow. I love MUFE Aqua Eyes in Mat Black, a two-in-one eyeshadow and liner which is guaranteed to stay put through it all and it's completely smudgable, if you want it that way. Line both top and bottom lash lines with a little smudging on the top for a simple anytime look. Add a little more for a mored edgy look! Bonus: a little bit can be used to fill in brows. I said little bit!
Mascara: I am an admitted mascara junkie, so I'm going to say that you need to bring some with you! I use Cover Girl's Lash Blast Volume (the orange one)... with about 3 coats. Every day. That's just my look, but it's never intense or edgy or looks like I need to be finishing the rest of my 'goth' look. It works well with my lashes and I can apply many (probably up to 5) without it looking terrible or giving me the dreaded 'tarantula eyes' look. So, depending on your lashes, find one that works well and is buildable.
Lips: I also have a bit of a lip gloss addiction. There was a time when you couldn't catch me without a tube in my pocket. I loved that having it in my pocket would warm it and make it easier to apply. I had a problem, yes I know

That said, I believe someone everyone should always have (traveling or otherwise) is a clear lip gloss. I love MAC's Clear Lipglass. It's actually designed to be work with lipstick, lip pencils or just by itself so you know it won't do anything you don't want it to do other than add shine. It also can add just a little hint of shine or give you that full-on wet-shine look. It's not super sticky so your hair won't get stuck if it's windy and it doesn't seem to do anything else really other than be pretty. The stuff lasts forever, so while a tube of $14 clear lip gloss may seem ridiculous, it's completely worth it. Can be layered over foundation for a 'nude lip' or on its own (remember you can have the black intense eye look for going out, so neutral lips are perfect!) if you'd like to keep your lip's natural color.
Blush/Bronzer: I only use a blush when I'm going out or if I haven't gotten enough sleep and my skintone is dreadfully in need of some livening. And since I've already comitted to an intense eye with a neutral-ish lip, I don't want anything that's going to make me look 'sculpted'. So, a simple color that's got just a hint of something will do the trick. If you want just a color to give your skin warmth, do it. A little bit of shimmer, highlight, whatever... just pick one that's subtle enough to complement your look and skintone without going overboard. I always use Jane Mineral Pillow Blush in "tender blush" because it's the color my skin naturally flushes... minus the blotchiness

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Brushes: I don't really use a whole bunch of brushes. True, the majority of my brushes are for the eyes but I hardly use them, preferring to use eyeliners instead with my fingers or a q-tip to smudge them. But, there are some things you absolutely need a brush for: blush and powder. So, because we're travelling, I use a double sided brush from Essence of Beauty: a contour and face duo. It's not a crazy expensive brush but it does the job pretty darn well if I can say so myself. Plus, with your subtle blush and ridiculously fine milled powder of the gods (MAC Select Sheer, hehe) you really can do no wrong!
I think I've said plenty on this, lol. But oh, if you want to bring your favorite perfume but are saddened that the bottle is too big, here's another little tip from me: go to Sephora and ask for a sample of your perfume. It'll come in this itty bitty spray bottle that can't be more than 5ml. Or, grab a solid perfume! Pacifica has great ones which are eco-friendly and at $9, you'll want to stock up! I love their Waikiki Pikake, it's like Hawaiian Jasmine! Or try their Lotus Garden, which is has a woodsy Oriental feel to it.
What are your must-haves for traveling?