It's very natural for the number of apps on your smartphone or tablet to increase after some time. To determine which apps require higher memory and CPU resources, you can download an app called "Usage Timelines", which you can find on the Play Store for free. You can also download the app "Pro CPU Monitor", but you'll have to pay Rs 126 for it. These apps show a list of the running apps and their current usage. Switch off the option "Start with system start" to avoid the app hogging resources every time you start your phone. Tap on the list entry to view a lot of information and to retrieve details. By using the "Display SysApps" option, you can examine hidden services. The option "Display time series" is quite interesting; it displays only a small symbol in the status bar that lets you see the CPU workload even when you have other apps open. This app lets you easily identify which actions or apps are responsible for high system load and so reduce the battery life. You must decide whether you really need a power-hungry app, and should get rid of such apps and look for alternatives.