The home button on Apple's iOS devices not only brings you to the home screen to see your apps, but is also used to bring up the multitasking menu and wake the device from sleep, which makes it one of the most frequently used buttons on the device.
Usually the button is quite responsive and will quit to the main menu after a short period of time, but at times when you press the button there can be a delay or it can even take a couple of tries before it responds.
- Reboot the device
Generally people rarely fully reboot their iOS devices and instead set them in sleep or standby mode when not in use, which is convenient but might allow any problems that occur to not be properly cleared over time, resulting in odd slowdowns or other unwanted behavior.
Therefore, the first thing to try is to reboot the system by holding down the sleep/wake button on the side of the device until you see the red slide control. Sliding this control will shut the device down, after which you can then press and hold the sleep/wake button to start up the device again.
- Calibrate the home button
iOS devices support an option to calibrate the home button, which requires interaction with a stock application like the Calendar, Weather, or YouTube. To make use of this option, open one of these apps and then with the app open press the sleep/wake button at the top of your device until the red slider control appears. As soon as you see it, press the home button and keep it held down until the red slider disappears. The device's home button has now been calibrated.