What actually Slows down your low-end android smartphone.

Do Android phones and tablets slow down over time?
Many people seem to think so. We’ll look at the reasons
why devices slow down and how to battle slow downs.
This problem isn’t necessarily unique to Android — try
using an iPad 3 with iOS 7 and feel how slow it’s
become — but it does seem to be reported by many
Android users.

Operating System Updates and Heavier Apps
Your Android phone doesn’t have the same software it
had a year ago. If you’ve received Android operating
system updates, they may not be as nicely optimized for
your device and may have slowed it down. Or, your
carrier or manufacturer may have added additional
bloatware apps in an update, which run in the background
and slow things down.

Even if you haven’t seen a single update, the apps running
on your device are newer. Whether you’re using newer
apps or updated versions of the same apps you were using
a year ago, apps seem to become heavier over time. As
developers gain access to faster smartphone hardware,
games and other apps may be optimized for this faster
hardware and perform worse on older devices. This
seems to happen on every platform. As the years go by,
websites become heavier, desktop applications want more
RAM, and PC games become more demanding.

How to Fix It: There’s not much you can do here. If your
operating system seems slow, you may want to install a
custom ROM like CyanogenMod that doesn’t have the
bloatware and slow manufacturer skins many devices
include. If your apps seem slow, try hunting for more
lightweight apps.

Background Processes
You’ve probably installed more apps as you continue to use
your device. Some apps open at startup and run in the
background, consuming CPU resources and taking up
your device’s memory. If you’ve installed a lot of apps
that run in the background, they can slow down your
device. Android offers real multitasking, so apps can run
in the background.
If you’re using an animated live wallpaper and have a
large amount of widgets on your home screen, these will
take up CPU, graphics, and memory resources. Slim
your home screen down and you’ll see an improvement.
Apps running in the background can also consume
resources. To check what apps are using background
processes, visit the Apps screen in the Settings app and
swipe over to the Running category. If you don’t use an
app that’s running in the background, uninstall it. If you
can’t uninstall it because it came with your device, disable
it . Don’t just end the service — it will automatically
restart.
How to Fix It: Disable live wallpapers, remove widgets,
and uninstall or disable heavy apps you don’t use. In fact,
you may want to uninstall all the apps you never use.

A Nearly Full File System

Solid-state drives slow down as you fill them up , so
writing to the file system may be very slow if it’s almost
full. This will cause Android and apps to appear to be
much slower. The Storage screen in the Settings app will
show you how full your device’s storage is and what’s
using the space.
Cache files can consume quite a bit of storage space if
allowed to grow unchecked, so clearing cache files can
free up disk space and make your file system perform
better. To clear cached data for all installed apps at once,
open the Settings app, tap Storage, scroll down, tap
Cached data, and tap OK.
How to Fix It: Uninstall apps you don’t use, delete files
you don’t need, and clear app caches to free up space. You
can also just perform a factory reset and only install the
apps you need to end up with a like-new device.

If your device is still slow you can factory reset your phone and install light weight apps you will actually use. It may seem m fun having a lot of apps but it won't be so funny when you have to wait for almost a minute before an app actually opens. Use your device right and keep enough Ram and Internal Storage space free for your device to run properly.

And Always Remember
"Google Is Your Friend"