Don't stress about it so much.
A Battery cycle refers to, more or less, one mostly full discharge and recharge. Typically, your battery should be rated for somewhere in the neighborhood of 1000 cycles. Eventually, the battery just won't hold a charge for as long as it did when it was new, but that's why batteries are easily and affordably replaceable. It's a consumable part. If it dies prematurely (which is the only thing you should really need to pay attention to cycles for), then it's covered under your warranty. The 'Battery Cycles' indicator is mainly there so that you can diagnose this. If, in a years time, your laptop's battery only lasts half as long as it did when it was new, but you've only used say, 400 cycles, well, that's not performing up to spec, and it should be covered under your warranty. If you've used 1500 cycles (doing that in a year would be some pretty heavy and impressive use though, I've gotta say), well, that's to be expected. You used your battery a lot, and it wore out.
Use your laptop as normal. Battery cycles are not a scarce and precious resource to be hoarded. 12 cycles in about a week and a half sounds pretty normal for a new laptop being used heavily to me. That's about, what? 6 hours/day unconnected to a power source? If you're using it on the go, that's a perfectly reasonable amount of consumption.
Applications and Menu Bar items
Most of these can be easily configured in:
System Preferences → Users&Groups → Login Items
LaunchAgents and LaunchDaemons
Some applications are cannot be configured in the System Preferences (e.g. Sophos AV Scanner, HandsOff Firewall,...) It's best to configure them in their own application to assure that everything runs as designed and intended.
You can look for related LaunchAgents and LaunchDaemons in:
~/Library/LaunchAgents ~/Library/LaunchDaemons
/Library/LaunchAgents /Library/LaunchDaemons
/System/Library/LaunchAgents /System/Library/LaunchDaemons
Startup Items
After I installed the multi-boot utility rEFIt, it copied a file rEFItBlesser
which is run at startup.
Items that run at startup can be found in the following locations:
~/Library/Startup Items
/Library/Startup Items
Best Answer
iOS 11.3 brings iPhone Battery Health (Beta). This new feature made available in this update provides users with info about the health of their battery, allowing them to determine if the condition of their battery is affecting their iPhone's performance.
Go to Settings → Battery → Battery Health (Beta). If your battery is functioning correctly, you will see the left message. If not, you will see the right message and you can tap Disable to disable the performance management.
You can read more about this feature in the Apple KB article
Without updating to iOS 11.3, you can still determine battery health.
If you don't have one of these devices with at least this version of iOS, your device is not being slowed regardless of the state of the battery, unless you've enabled Low Power Mode either manually or when the battery reaches 20% (and disables at 80%).
If you have one of these devices, you can check if your battery is poor using an app:
To know more accurately, you can run the Geekbench benchmark.
Make sure Low Power Mode is disabled, then run the Geekbench benchmark (not the battery benchmark, that's for analysing your battery itself and not its effect on iOS) and note your score. If it's more than 500 points less than the expected number (given below), then this indicates a potential problem.