Welcome to Android Central! Remember that a 16 GB device usually only gives the user about 10 GB of usable space, after accounting for the OS and preinstalled bloatware. If you use an SD card, that can help offload some of your data, but it's really only good for media files and documents, not for app installation. If it's important to you to install lots of apps, next time get a device with at least 32 GB of internal storage.