You should keep your desk at your office clean. The same should be done with your computer desktop.
Does your Mac need to be reformatted? Probably not. But lets face it, sometimes it’s nice to get a fresh start.
Your Mac, like most things in life, needs to be cleaned and maintained. OnyX is the best tool for this job.
Stop quitting all of your apps to save battery life. Quitting iOS applications does not save battery life, it actually has an adverse effect.