[Galaxy Note GT-N7000 Q&A, Help & Troubleshooting] AndroidSlave:
TYPICAL REASONS FOR WAKELOCKS & APP SUCKERS, KNOWN ISSUES:

- Any kind of messengers, social clients – like Skype, Facebook, Twitter, etc. Any of those, who want to be online, receive a push messages, sync every while. If it’s must to have them, disable it in accounts sync settings, and disable notifications in each app’s setting.

- “Energy savers” – Green Power, Timeriffic, etc. They mess with the system power policy, if you choose to enable/disable wi-fi, gps, data, Bluetooth, etc. Especially, Samsung’s one is known as problematic.

- “Soft-buttons”, so called “power button savers” – like ScreenOff & Lock and such. Related to previous group. Let the hardware do the job.

- Task killers - If it kills some services in the middle of their action, it will cause’em start all over again or even stuck, and eat your precious battery resources. If you have to use it (like in case with JB 4.1 memory leak issue, do it manually).

- Your sound settings – screen vibro & sounds on tap, haptic feedback – disable it.

- Media Scan – process, that will run after each fresh install & reboot. Typically takes about 10-15 minutes, runs on high CPU frequency. If stuck more than this, causes no Deep Sleep (can be seen in CPU Spy app) – you have an issue with Media Scan. It can stuck on large files directory – nothing to do here, unless you can reduce files number. Another case – problematic memory cluster, and there is only solution to back your data, format your storages, and start over.

- Startup - Check it – do you really need this entire long startup list? Throw some; it will only make the system act better.

- Accounts sync – again: Minimize your list. Drill down every account setting, Google especially: Picasa, Google Disc, G+, etc.

- App settings – always drill down your app settings – it may be some nasty hidden setting, that enables your app to be in constant action. No concrete advise, treat each app individually.

TIPS:

- Always perform clean install! Backup your stuff – App2zip (free on market) app, Titanium, whatever – spend some time for formats and setting up your settings, you will only have profit on this.

- Don’t judge your battery consumption right after new rom/kernel install. Especially in the first hour, while Media Scan is busy with scanning your storage. System needs some time to settle.

- It is highly suggested, after you installed all apps and made your configurations, to reboot recovery and clean your cache & dalvick.

- If you’re installing custom kernel and any .zip flashable files, don’t do it in the same time with rom flashing. Flash the rom, reboot system, let it settle, then reboot recovery again, flash your kernel/mods, let it settle again.

- WI-FI sleep policy: leave it on “Always”. Note’s wi-fi chip consumes nearly zero energy, and it would be much healthier to leave it on.

- WI-FI home network: if you’re on dynamic IP, set to maximum your DHCP lease time in router setting, and bind your device to the MAC address. Also, fix your WI-FI channel and frequency both on device and router.

- *Don’t mess with Fast Dormancy app, if you don’t have dormancy related wakelocks, or if you don’t know your cell operator dormancy setting! And, on JB 4.1 it’s sometimes more preferable to leave it on, than to deal with some weird wakelocks, that may appear. Another case – if your operator setting for dormancy is “off”, app won’t discover it, and, actually, you may enable it instead of disabling it.

Wakelocks - XDA Wiki - take a look at it, may be very useful.