As for the Galaxy tab 3 I saw that it gets quite laggy when some apps are installed....
Here's what I do to manage and Maintain my tab:
1.) The number 1 thing I do when I unbox and setup my device is install Battery Doctor.
-This app I found charges your device in a certain way to prolong battery survival and it does it in 3 steps.
-This app also has modes that you can turn on that you can customise to a setting of your desire.... it comes with 3 as standard. Extreme mode and super saving mode helps a lot when your not using it for a while.
- Lastly it has optional widgets that you can put on home screen that optimises the battery, cleans apps/cache.
2.) Another one that you may find as useful is MobileCare. This app has a battery saving mode, App manager and Task killer if your are looking at JUST battery. This app offers a much simpler way to reduce battery drainage from the click of a switch power saver mode is enabled.
Performance Enhancing Apps
So to have optimum performance without rooting your device or overclocking here is what I use:
1.) MobileCare - As well as battery saving there a few other tweaks it has that I didn't mention above....
-Game Speeder- this basically give you a choice of the app you wish to run and it will basically optimise the app/game for you so it runs as smooth as possible.
- It also has a built in Antivirus/Anti-theft feature which also speeds and improves performance if there are viruses or ads slowing you down.
- Task killer- this app basically kills all apps and processes so the ram is nice and fresh.....1gb RAM can get packed sometimes.
2.) Memory Booster- This apps really helps as well.
-It features a Quick boost mode when you just want free space and instant performance.
-It also shows proof of it working in the form of a monitor and a diagram showing ram before and after.
-This app also features its own task killer and a boost log.
-This app is really useful because it comes with some really nice small compact widgets that you can do the quick boost function and task killer from a simple tap on the home screen instead of actually opening the APP itself.
Please feel free to add on to this list....I wrote these because they were the most efficient in terms of being able to use them seemlessly.
This thread is ideal for those who havn't got root access and want to maintain their tab 3's.
I will upload links Shortly.
edit-----I know the Task Killer mentioned dosnt kill ALL the apps and processes. However the point of that app is to close all of apps and processes that wouldnt harm your system if they were closed, so you have you normal open apps that need to be closed and then some background apps and clears cache etc.