July 23rd, 2012, 09:29 PM
Join Date: May 2011
Device(s): Current - VZW Galaxy Note 2
Retired - Moto Droid X2, Moto Q9M, HTC Vogue, HTC Imagio
Carrier: Verizon Wireless
Thanked 56 Times in 48 Posts
Generally speaking you shouldn't need them. However it does also depend on if you are on stock or custom rom. The stock motoblur interface is a real memory hog. As such you might experience lags and performance issues with it and might benefit from a cache cleaner.
The Android system does a good job killing tasks on its own but people use them anyway. Task killers are pointless in my opinion.
Juice defender seems to do a good job managing battery life on older devices. I have not needed to use any of these but what I have done is install cm7 rom on here which in my opinion is the most efficient rom available. There are lots of performance settings and customizations built in.
My advice is to use it for some time and see what you like and don't like first. Read the stickies about freezing apps and other troubleshooting stuff that has been done so you can get an idea as to how far you want to go and what programs work best. Let us know if you have any more specific questions.
Current ROM - Cyanogen Mod 7.2
Flashing rule to live by: Always remember to wipe Cache and Dalvik Cache!