An Android smartphone is challenging to use for uncertain and aged fingers, but this problem can be easily solved by downloading an app that supplies a 'home screen replacement', also called a launcher. The bolded app titles below can be previewed and installed via the Google Play store on your Android device, or by navigating to play.google.com on a desktop PC and logging in with the Google account set up on your Android device.
Upon installing one of the below 'launcher' apps, when you tap "Home" button you will be prompted to choose a preferred launcher. If you do not wish to be prompted again, tick the "make default" option then tap "OK".
Wiser (free) focuses on doing the everyday things easily. You will see a new main screen with six large icons: Contacts, Dialler, Messaging, Camera, Gallery and Applications. If your smartphone is less than a couple of years old and has Android 4.3 or above, you can swipe left to see 'Notice Board', a simplified app notification screen. Wiser is a smooth and light little app, using just 15MB of RAM, so it should not slow down even a very cheap phone with less than 512MB of total RAM.
Simple Senior Phone (free): This simplified launcher is ideal for those with poor eyesight. A simplified home screen with large icons and a list of four important contacts. It offers less customization, but it can block annoying users and default apps on the device.
Large Launcher Senior Phone (free): This launcher is so simple, there is no way to customize (i.e. mess up!) the screen. You can only slide up and down or tap on apps to open them. It has simplified notifications, SOS for sending current location and many other features are available.
Big Launcher is another simplified launcher for seniors, with a free or paid ($10) option, depending on whether you need extra customization and no restrictions to sending messages.
Necta is another 'home screen replacement' which is a 3-day trial, then paid. It also supplies its own custom dialler, SMS camera and gallery apps. There are also three dedicated quick-dial shortcuts. These three "favourite" contacts will also notified via emergency SMS if the user activates the SOS app. Sending an SOS is as simple as tapping on "SOS" on the home screen (on some phones, just waving a flat hand slowly over the screen three times will send the SOS message). Another app called 'Position' can send position information to favourite contacts.