Features & Use
Test device: Samsung Galaxy Note 2
Android version: 4.1.2
In the main page of the app, it gets straight down to business. Here you'll see a list of apps that are currently running in the background along with information about what difference the app makes in the CPU workload. You can also see how much memory it uses. The last fact is important mainly important for older devices with less than 1 GB of memory. Your device's amount is shown in the process list, as well as how much is left and how hard your processor (the CPU) is working. On the top right corner, you'll find a button, which hides the sorted processor list. You can sort these by CPU last, memory use and by the app's name.
If you want to find out which apps are emptying your battery and slowing down your smartphone, you should look for the ones in the background, which are taking up more than 5% of your CPU workload. As soon as you've found the described app, you can tap on it for further details like the process ID, the package name and the app status. An app can be found in the background or foreground and can also be a service. The latter are there to update the respective widgets on your homescreen. Basically they have a right to exist, yet shouldn't take up more than 5% of your CPU workload over the long run.
By choosing the ''time series'' button, you'll be shown a graphic of the CPU workload in your notification area. This is meaningful if you want to test an app's CPU-workload in the foreground that could potentially be milking the headset's energy. With games, it's important to pay attention that they're utilizing the GPU, which isn't shown in this app.
In the top right corner, you'll see the system apps. This isn't exactly that meaningful, since you can't deactivate this app for the most part anyways, without running into errors.
Usage Timelines Free is a very useful tool, which serves the purpose of analyzing the energy-thirsty installed apps. All the important information is clearly presented. On the other hand, it's missing a long-run analysis, which lets you observe specific apps over longer periods of time.
Screen & Controls
Usage Timelines Free is a relatively intuitive app to control, even for the not-too-computer-inclined folk. What I think it's missing is a small tutorial at the beginning, which would've been helpful to explain all the various terms. Other than that, the app is completely satisfactory in terms of design.
Speed & Stability
Usage Timelines Free works fast and stably and doesn't change the results.
Usage Timelines Free is, like the name says, free and is financed by ads.