Smartphones have become more than anyone could have imagined. We use them as a communication device, to pull analytics reports, to connect with colleagues on social media, and even to help monitor core IT services. Yet, it can be hard to know which apps are the most valuable to keep around or rely on during a hectic schedule.\nTo give you some ideas, CIO.com asked several CIOs which apps they use each day, the ones they rely on the most as part of their routine. Some of the apps they use are surprising (e.g., games to pass the time in a meeting) and some are more for personal use.\nBrad Schick, CTO and vice president of engineering at cloud service provider Skytap\n1. Slack\nSchick says this is the defacto app for collaborative messaging at Skytap, although he says there are a few \u201cstubborn\u201d users who still send SMS texts (and he obliges them).\n2. LinkedIn\nSchick said LinkedIn is a big part of his job. \u201cAs a tech person, it took me a few decades to realize that people and relationships make the world go around,\u201d he says.\n3. Evernote\nThis note-taking app is the one Schick uses on his laptop to take notes, but on his phone, he reviews the notes or reference some data points in a \u201clean back\u201d way.\n4. Clash of Clans\nYou never know if you end up at a meeting that is going to take longer than expected and might not apply to you, he says, which is where this popular game comes in handy.\n[Related: The best Android apps of 2015]\nDave Wagner, CTO at data management company OpsDataStore\n1. Skype\nSkype is his go-to app for working with technical folks. \u201cI maintain global relationships with multiple technical architects, evangelists and visionaries whom I have met over the years. Like myself, I\u2019ve found that many technical architect and visionaries were very early adopters of Skype, and, in fact prefer to maintain contact in this fashion versus more \u201csocial\u201d messaging platforms,\u201d he says.\n2. OpsDataStore console\nNot a big surprise that Wagner uses an app for his own services. This data analytics app, which runs on Tableau, allows him to keep tabs on internal systems and applications.\n3. LinkedIn\nWagner says he uses LinkedIn to keep tabs on technologists and to vet qualified personnel. He says it doesn't have the high signal to noise ratio of other social media platforms.\n4. Chess.com\nAlmost every IT leader who shared their app picks mentioned at least one game. \u201cThis app allows me to catalyze creative problem solving in my professional life,\u201d says Wagner. It\u2019s also great for \u2018down time\u2019 when you want to exercise your mental muscles.\u201d\nBrian Sprang, CIO at Quest Federal Credit Union\n1. Keeper\nThis is the go-to app Sprang and his team use for password management. He uses it for their multiple portals for secure browsing and to create and store strong passwords.\n2. Facebook Pages Manager\nA bit surprising, this app is an integral part of Sprang\u2019s day-to-day duties (he is the liaison for technical marketing activities as well). The app lets him check social media campaigns.\n3. Deliveries\nThis unique app provides a quick glimpse into any packages he\u2019s ordered and allows him to see reports on shipping activity and track incoming packages.\n4. Tweetbot\nThere are many options when it comes to checking Twitter activity, but this app has some powerful syncing capabilities to make sure you are seeing the latest posts and feeds.\n5. Classdojo\nAs a personal app, Sprang uses Classdojo to communicate with teachers and to view any disciplinary issues or positive feedback from the classroom for his kids.\n[Related: 12 essential apps for your brand-new iPhone]\nDanny Miller, System CISO at Texas A&M University\n1. Syncplicity\nInstead of Dropbox, Box.net or a host of competing products, Texas A&M uses this app due to the simple user interface and geo-fencing features.\n2. LastPass\nAs most IT leaders can attest, it is critical to use a password manager at all levels of IT. \u201cIt's still a bit clumsy on smartphone platforms, but it is the best when managing passwords and access to various platforms where you need solid security,\u201d says Miller.\n3. Duo\nMiller says he uses this app for multi-factor authentication to secure Web apps. \u201cIt works so well that I'm even rolling it out on development teams for next-generation business applications that use live data for testing the applications,\u201d he says.\n4. Arlo \nFor personal use, MIller relies on this Netgear home security app to keep an eye on his house when he isn\u2019t home. It works with interior and exterior cameras.