As mentioned in my various articles, keeping your operating system and applications updates is a critical component to good overall security.
Apple released IOS 10.3.3 yesterday, and amongst all of the bugs it fixes, there is one nasty security vulnerability that justifies installing it now. Right now. Do it. I'll wait. Come on, we don't have all day.
Put Apple's banal sounding description aside for a second ("A memory corruption issue was addressed with improved memory handling".) This vulnerability comes from the Broadcom BCM43xx wifi chipset (CVE-2017-9417) and allows an attacker to execute code on the targeted device with kernel privileges.
To be clear, millions of Android smartphones (e.g. HTC, LG, Nexus and most Samsung devices) are also vulnerable to the BroadPwn vulnerability.
Google also issued the BroadPwn fix in its July patch bundle (you are receiving the security updates for your phone right?)