What are some of these battery saving apps you mentioned?
I could use a few of them.
one of those launchers called APUS launcher makes your android look any way (icons, wallpaper, app page switcher (i.e. cube mode, simple left/right swipe, swipe up/down to bring up the app icons etc... anyway...it has like a billion downloads and is very popular....but the best part is the home screen you swipe left and it has a boost mode which turns off battery draining apps (unused/idle ones) and give your phone a performance boost.....
of course the alternative is to disable google play all together ( which runs constantly in the background anyway draining batt)....and use a 3rd party app store like 1 mobile or even just download the apk manually and sideload/update the apps this way (what i usually do if I have access to my computer and IDM downloader)....it saves time and bandwith/data on a mobile phone doing it this way....(not to mention batt drain due to always on wifi required to download most apps.....
also c cleaner is good for your mobile.....it's had some recent issues though so just read up on it as some people claim its been hacked by malware?? anyway its task killer and cookie cleaner is very good at boosting your phone and killing apps.....
also its good to declutter your app's that are redundant....for example I tried out several bible apps and settled on BLB bible (tecarta is also good) and deleted all the other apps that were redundant....like hymn book apps I deleted to only 2 verseview and hymn lyrics.....a lot of the task killers advertise a ton of "features" but its really just full of adds and nothing worthwhile....
also i disable apps I never use like google books, google movies, google music....there are just tons of better apps than google's simpleton apps....