Do I need mackeeper?

Do not install MacKeeper (and how to uninstall it if you have):

https://discussions.apple.com/docs/DOC-6221

How to uninsrall it:

http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/

It contains a major security flaw, recently noted:

http://www.macnn.com/articles/15/05/08/contentious.utility.ignored.apple.guideli nes.created.zero.day.exploit.128538/

There is currently a class-action against MacKeeper:

http://www.macworld.com/article/2927032/ads-for-mackeeper-refunds-will-run-on-fa cebook.html#tk.nl_mwbest

(Please note that references to the original developers, Zeobit, also now refer to Kromtech Alliance Corp, who acquired MacKeeper and PCKeeper from ZeoBit LLC in early 2013.) And in that context the foregoing also applies to their latest offerings,Advnced MacKeeper, AdwareBuster and AdvancedMacCleaner ,which were quickly found to not identify much of the adware around.

Only if you want to ruin your computer.

You do not need MacKeeper or anything like it.

See this article for addition information.

Effective defenses against malware and other threats

Best thing you can do to protect your Mac is to make sure the macOS is up to date.

Open the App Store then select Updates.

If you have it installed, uninstall it asap. How to uninstall mackeeper.

Mackeeper sounds like the Mac version of "Driver Booster" and "Registery Booster" and other completely unnecessary programs. I wouldn't even poke at Mackeeper with a 10 meter long stick.