Every three months or so, I look back at the mobile apps, devices, and wearables I reviewed during that period. I ask myself one question: What have I continued to use and enjoy after my initial tests? This summer, three products passed the acid test.\n1. Kindle Oasis is a top-notch ereader\nAt first, I resisted buying Amazon's latest Kindle ereader. It\u2019s expensive, starting at $290. I wasn't sure why I needed a dedicated ereader when I could read ebooks on my iPad mini. And it's yet another device to recharge when traveling.\nAs it turns out, I was wrong on all accounts. The Oasis quickly reminded me that, unlike an iPad mini, dedicated ereaders keep you focused on reading ebooks. The "experimental" web browser on Kindle ereaders is dismal, so jumping from an ebook to Facebook or Instagram and getting distracted simply doesn't happen. It's a rare instance in which a product's limitation is actually a user benefit.\nNow that it's summer, there's another reason to take an ereader to the park or beach instead of a tablet: ereader screens are much more legible in bright sunlight. Tablet screens have improved in this regard, but they still don't compare to dedicated ereader displays. Unfortunately, most tablets and ereaders aren't waterproof, so if you take one to the pool or beach, you might want to put it in a waterproof pouch. (I bought a set of three pouches on Amazon for $5.71.)\nThere's no denying that Oasis is expensive. However, if you want a very thin, light Kindle ereader with a protective cover, the only other option is a Kindle Voyage. That device starts at $200, and the Amazon cover starts at $45. So you're looking at a total price of $245 or more.\u00a0Oasis's $290 (and up) price includes a premium cover with its own battery. So the price difference is only $45, which is worth it. You could also buy a basic Kindle starting at $80 or Kindle Paperwhite starting at $120, but they're not as thin or light as Voyage and Oasis.\nFinally, Oasis, unlike other Kindle ereaders, can go "months" before it needs a recharge, according to Amazon. Initially, I didn't think this was a big deal. However, now that I've traveled a few times with Oasis, I appreciate the fact that I don't need to pack its charger along with all my other power accessories.\n2. Email could become your go-to mail app\nEmail is a free iOS app that I continue to use after\u00a0I reviewed it in May. Countless mobile email apps exist, but Easilydo's Email is particularly good at unsubscribing you from email subscription lists.\nI also prefer Email's search capabilities to those in many other email apps, especially the native iOS Mail app. Searches are deeper and faster in Email. The app's travel "assistant" is pretty cool, because it shows all travel-related email in one view. Likewise the "bills & receipts" and "packages" assistants are also useful. However, I wish an iPad-optimized version were available, and there's also no Android equivalent. If you're looking for a better email app for your iPhone, Email is definitely worth a try.\n Easilydo\n3. Easily mark up images with Annotable\nAnnotable is a freemium image annotation tool for iPhone and iPad that makes it easy to draw annotations on screenshots or other photos with a finger or, on an iPad Pro, an Apple Pencil stylus.\n Ling Wang\nOther Annotable tools also add value, including "Loupe," for magnifying part of an image, and "Blur," for smudging sections of photos for privacy or other reasons. However, these utilities require in-app purchases. I recommend giving the app a try and, if it fits your workflow, spring for the reasonable $8 purchase that unlocks all of its tools.