You want to wait until the last minute to pack? Go for it. Prefer to read up on your destination only when you're on the plane? Sounds good. But there are some things that even the most fly-by-the-seat traveler must do before setting off. Here are 11 planning pitfalls—irksome oversights and full-on show-stoppers—that are brilliantly avoidable, as long as you address them well in advance. From getting the proper immunizations to breaking in new shoes, here's what you need to be thinking about in the days, weeks, and months before your next trip.

Get Immunizations

Heading to Argentina? Make sure you have your typhoid shot. Going to China? You'll need a hepatitis A vaccine. Since getting the proper vaccinations means booking medical appointments and sometimes requires more than one dose (often spaced a few weeks or months apart), it's not something you can do at the last minute. The CDC's Travelers Health tool offers comprehensive information about vaccination recommendations by country.

Keep in mind that even in countries where special vaccinations aren't necessary, it's important to make sure you're up-to-date on all your routine vaccinations—including measles-mumps-rubella and diphtheria-tetanus-pertussis.

Break in New Shoes

Breaking in new shoes, especially the pairs you'll be using intensively on your travels, should never be left to the last minute. It can take days or weeks of short-term wear to effectively and painlessly get a new pair of shoes vacation-ready. Try to cram the breaking-in process into a few days pre-trip and you may end up with blisters that will not only make you hate the shoes but can also make walking uncomfortable right from the start of your trip.

Download Movies

Traveling with your own entertainment is great. Layovers, long flights, and delays simply aren't as bad if you can fill the time catching up on movies. But even with a fast Internet connection, downloading movies is still a surprisingly slow process. As a general rule, it's a good idea to prepare your tablet (or phone, or laptop) at least a day in advance, giving your device plenty of time with a fast connection so you can add whatever movies, TV shows, or books you want to take. Because waiting for a movie to finish downloading is a terrible reason to miss a flight.

Order Special Meals for the Plane

If you're expecting a vegetarian, vegan, gluten-free, kosher, halal, or other special meal on a flight, you can't leave it to the last minute. Most airlines require at least 24 hours' notice to accommodate alternative meals. In fact, the best time to make your request is at the time of booking, when you're already on the website or phone and already thinking about it. Your hungry future plane self will thank you for it.

Update Your Operating System

Downloading the latest operating system for your phone on the way to the airport can throw a major wrench in the works. Not only does it mean rebooting at a time when you're likely to need the device to make last-minute phone calls or check your flight status, but your phone's fresh outlook on life means you may need to re-log in to some of your apps. And if you're a person who doesn't know all of your passwords off the top of your head, this can leave you without travel vitals like itinerary information and access to communication tools.

Book House Sitters and Pet Sitters

It's always wise to lock in your preferred house sitter or pet sitter well in advance of your trip. This goes double during the summer and around the holidays, when home-care providers are in high demand and book up quickly. Even if your plan is to souvenir-bribe a family member to pick up your mail or pay a neighbor kid to clean the litter box, you'll need to make sure they'll be around to manage the home front while you're away.

Download and Update Apps

Without a fast connection, downloading and updating apps can be frustratingly slow. And deciding which new apps you'll need (which HDR camera app? Which map app? Which public transportation app?) can be a time-consuming process. That's all to say that it's a good idea to download new apps and update any apps you'll rely on while traveling (since older versions may crash or just not work as they should) the day before you leave, at the latest.

Sort Out Your Adapter and Converter Needs

Will your electronics simply require an adapter, or will they need both a converter (also called a transformer) and an adapter? These are important questions to clear up well before you travel. Many electronics (such as Apple phones and tablets) have a converter built into the charging plug, so if you're traveling somewhere with 240 V current, you'll just need an adapter for the plug shape. But if you try to plug in something (for instance, a hair dryer or white-noise machine) that doesn't run on dual current, you'll break it. Figure this out before your trip and avoid electronic meltdowns.

Book Popular Restaurants

If you've got your heart set on eating at a specific restaurant in a city you're visiting, you should seriously consider reservations. Because if a restaurant is popular enough for word of it to have reached foreign shores, chances are it's going to be hard to get into. Brush up on your language skills and make the phone call, or if you have a credit card with a concierge service, you can enlist the help of a professional. OpenTable allows you to book online at many restaurants in the U.S., as well as an increasing number of spots in 19 countries and regions including the U.K., Japan, and Mexico. Or use a country-specific restaurant-reservation site such as Lafourchette in France.

Check Your Passport's Expiration Date

Are you traveling anywhere within the next year? Then stop reading this, go find your passport, and make sure the expiration date isn't within six months of your travel dates. Take this small but vital step because some countries won't allow you in if your passport expires too close to your travel dates. Known as the six-month passport validity rule (and the similar three-month passport validity rule), it can ruin a vacation even before it begins. USA Today has an overview of countries and regions that enforce validity rules.

Check Baggage Restrictions of Connecting Airlines

On some connecting flights, you only need to know the baggage restrictions of the airline you booked through. But other times, you'll be expected to abide by multiple airlines' baggage policies. And if you book a separate flight at your destination, you'll need to make sure your baggage abides by those rules or risk paying a hefty fee. It's an irritating process, and on some foreign carriers without clear information posted online it may require a phone call, but think of it as better than getting to the airport and discovering you'll need to pay an extra $50 to bring your toothbrush and clean socks.

You Might Also Like:

 What to Know Before Going Someplace New

 10 Things to Do Before a Trip

 How to Fly Like a Travel Pro

This article was originally published by SmarterTravel under the title Pro Tip: Don't Leave These 11 Things Until the Last Minute. Follow Christine Sarkis on Google+ or email her at editor@smartertravel.com.

(Lead Photo: Thinkstock/iStock)

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