Whether you're a longtime smartphone or tablet owner or unwrapping your very first one over the holidays, there are many thousands of new applications ("apps") for your device.

In fact, therein lies the problem: with more than a million apps at Apple's App Store (for iPhone, iPod touch and iPad) and Google Play store (for Android-powered mobile products), finding something new to download for your phone or tablet can be overwhelming.

No problem, as we've curated some of the newer "must have" apps for your collection. Here is a look at the year's best â€" divided into various categories for your convenience.

Unless specified otherwise, all of these apps are available for iOS and Android devices. And hey, be sure to suggest your favorites too.

MORE: The best apps for Windows Phone

LIFESTYLE

Learn a new language with Duolingo: Learn Languages for Free, a clever app that makes it fun to tackle Spanish, French, German, Portuguese, Italian or English. With bite-sized lessons, you'll start off matching words with pictures, hearing what they sound like and saying words into your phone or tablet. This free app also has a "gamification" element for extra incentive, including a trumpet that celebrates your advancements, earning XP (experience) points and hearts, and keeping track of your progress.

Have an old iPhone, iPod touch or iPad lying around? Turn it into a wireless surveillance camera with the help of a free iOS app called Presence by People Power. Once downloaded and installed, simply launch the app and place the rear-facing camera somewhere in your home â€" perhaps serving as a baby monitor, nanny cam or a way to keep an eye on your pets while away at work. Now, wherever life takes you, open the same app on your main phone or tablet to see what's happening in real-time at home.

One of the most buzzed about apps of the year, Snapchat is a free messaging app that lets you take photos or record videos â€" called "snaps" â€" which are then sent to someone to view on their phone or tablet. Unlike other messaging apps, snaps can only be viewed for up to 10 seconds, after which they self-destruct â€" never to be seen again. Controversy over "sexting" aside, Snapchat might in fact be a better alternative than having your digital comments and photos archived and public forever.

Illustrating what's possible in mobile shopping, the free glasses.com app for iOS lets you try on thousands of pairs of glasses and sunglasses, virtually speaking, to see what the frames look like on your face. In fact, your device's camera uses 3D technology to capture your face from different angles, so you can use your fingertip to move your head around to ensure they're a perfect fit. Or send them to a friend for their opinion. While the app is from the online eyewear retailer â€" yes, you can buy what you try on right from within the app â€" there's no hard sell from them.

If you're one of the many who enjoy flipping through weekly advertising flyers, Flipp for iOS devices will save you that mess of papers on your kitchen table. Select what retailers matter to you â€" whether it's a supermarket, electronics store, clothing chain, and so on â€" and then flick through the latest flyers that showcase new products and sales. Tap to zoom in and virtually "clip" a product. Search by keyword for store or product, or use the "discount finder" bar to see items 5 to 50 percent off the full price.

PRODUCTIVITY

At the iPhone 5c and 5s launch event, Apple announced it would throw in free copies of its Pages, Numbers and Keynote app (along with iPhoto, iMovie and GarageBand). Usually $9.99 apiece, these updated iOS apps help you remain productive on the go: Pages is an advanced word processor for writing and editing documents (with support for tables and charts); Numbers is a spreadsheet creator with more than 30 Apple-designed templates; and Keynote is an attractive and easy-to-use presentation maker that lets you add transitions, photos and interactive charts.

Serving as a free and versatile alternative to Microsoft Office, Kingsoft Office for Android and iOS supports 23 kinds of files including those created in Microsoft Word (such as .doc and .docx), Excel (.xls, .xlsx) and PowerPoint (.ppt, .pptx), as well as PDFs. A built-in file manager automatically organizes your office document, and gesture support means you can flick and swipe to get more done in less time. This app also supports popular cloud services such as Google Drive, Dropbox, Box.net and others.

Naturally, you don't carry around a flatbed scanner with you to digitize documents, receipts, business cards or hand-written notes and sketches. But some new apps can turn your phone or tablet into a powerful â€" and portable â€" scanner to accomplish these kinds of tasks. The free Prizmo (for iOS) and Handy Scanner (Android) offer "optical character recognition," which will make the text editable and searchable with very good accuracy (though not perfect). Prizmo can detect words in more than 40 languages (10 are built-in), while an optional in-app purchase has the app speak the text to you in one of many languages.

There are two problems with printing wirelessly from an iPad: you need an AirPrint-compatible printer and you don't have any print preview options. A new app called Printer Pro from Readdle ($4.99 for iPhone, $6.99 for iPad) addresses both of these issues. Print attachments, documents and web pages â€" right from your iOS device â€" to any Wi-Fi or USB printer connected to your PC or Mac. If you don't have a compatible wireless printer you'll be prompted to install a small and free application on your personal computer.

ENTERTAINMENT

Magazine lovers will likely "flip" over the newly-updated Zinio and Next Issue apps for iPad and Android tablets. Zinio's Z-Pass offering lets you choose 3 out of 300 magazines for $5/month (and the first month is free). With Next Issue, you can read more than 100 monthly magazines for $9.99 a month (or $14.99 a month for mags and popular weeklies including The New Yorker, Sports Illustrated, Time and more (first month is free). Both apps let you download and read popular publications cover to cover, share highlights with friends, and more.

Chosen by Apple as one of the best apps of 2013, Traktor DJ for iPhone ($4.99) or iPad ($19.99) lets you spin your music collection â€" whether you're entertaining friends at a house party or you're a professional DJ who doesn't want to lug your gear to a gig. Import tracks A and B from your iTunes music library and match or adjust the beats per minute (BPM) per track; when you play back the tracks you can adjust levels on the fly using a virtual cross-fader, and you can perform scratches using your fingertips. Set loops and samples, mark cue points for live edits and scrub through the tracks to find a spot in the song you're looking for.

Just in time to help with your New Year's Resolution weight loss goals, Six to Start's The Walk - Fitness Tracker and Game ($3.99) lets iOS and Android users fuse fitness with entertainment. When you walk around during the day, pop in your earbuds so you can hear a thrilling tale tied to your movement. You play as Walker, who is given a package that could save the world, but you'll need to progress through the game's maps, find clues and unlock new story elements over a 3-month period. Created by the folks responsible for the Zombies, Run! Fitness app, The Walk doesn't just record daily steps but provides some added motivation to go that extra mile.

Updated in December, the stellar and free VEVO app lets you watch more than 75,000 high-definition music videos, along with original content and live performances. Create customized playlists (saved in the cloud and synced to all VEVO-compatible devices), save videos to your "Watch Later" list and push what you're watching to your Twitter feed or Facebook timeline, if desired. Other features: match artists in your music library to VEVO videos; see what's trending (including a global "Music Map"); and opt for continuous play to keep the music coming.

Follow Marc Saltzman on Twitter: @marc_saltzman [1] .