Some time after getting a new phone or after wiping and reinstalling the phone's OS (or upgrading to a new version of Android), the phone starts to bog down and feel laggy compared to before. The hardware is the same (well, maybe the phone's battery has lost some charging capacity but the memory and CPU are still as good as when they were manufactured), so it must be something software-related, right? I mean, this problem happens with Windows PCs too (but not with Linux/OpenBSD...).

Not the thousands of stored SMSs and phone call logs

At first, I thought it might be the thousands of SMSs (and hundreds of phone calls) stored on my phone, which I keep for convenience. On my old Symbian OS Nokia these SMSs would really slow the phone down and so I would have to delete messages every month. But there's no good reason a modern phone can't handle nearly unlimited messages as easily as just a handful. But I gave it a shot, deleting all SMSs (first backing the messages and call logs with SMS Backup & Restore app) and phone calls, but it had no effect.

Not task killers

So then I wondered what mobile apps might be slowing the phone down. There are various task killer apps in the app marketplace and they will help you free up memory. I kinda of wanted to see a more granular view of what resources the various apps were using, like Task Manager or Activity Monitor. So I opened up Terminal Emulator and ran 'top' which doesn't redraw the screen like it would in other terminals, but simply writes out all processes to the screen again on each refresh. So it's slightly harder to understand.

Using an automated task killer is controversial. It's possible that using an automated task killer will confuse Android's memory manager.

Not the version of Android

Upgrading Android. Right after you load a fresh ROM onto your phone it is probably going to be as fast and responsive as it ever will be. Then some months down the line it's running slowly.

Remove widgets, V6 Supercharger your memory mangement, and turn off GPS

Here are the things that do help speed up your Android phone.

1) Remove some widgets and live wallpapers.

2) Advanced users: V6 Supercharger Script

3) In the end I think turning off GPS helped the most. This is likely due to location apps polling your location nearly constantly when it's on.