Reboots are not as regular an occurrence as they once were. Stable operating systems, SSDs and improved hibernation support in modern software means that it's easier to just close the lid or select the "Sleep" option in the shut down menu than go through the process of a fresh boot.
It also means that apps that auto-load on startup have an easier time accumulating so when you do inevitably restart, it comes complete with a bunch of programs you almost always don't need or want running in the background.
Applications have a tendency to install startup programs without informing you. Most are harmless -- take Google's update process for Chrome -- but others are just unnecessary. Do you really need Steam booting along with your virus scanner? How about the array of software Apple likes to have going constantly? I doubt many Windows users have their iPhones always plugged in or iTunes open.
Cleaning up your list of boot-time programs takes a few minutes, at most, though it can take longer depending on the program you use and how deep into the operating system you want to go. Here we'll pull out the three main methods... in order of increasing paranoia.
The Easy Approach: Microsoft's System Configuration Tool
This utility, which can be run by typing "msconfig" into the Start Menu search box or the "Run" dialog in older versions of Windows, gives you a straightforward way of disabling startup programs. You can't outright delete them, but that's a safeguard on Microsoft's part so that if you do turn off something important, it's simple to get it going again.
MSConfig looks at your registry, specifically the various "Run" and "RunOnce" keys as well as the user Startup folders, but doesn't go much deeper. This covers 95 per cent of all programs you'd be interested in disabling, so for a majority of users, it's good enough.
The Optimal Path: Piriform's CCleaner
CCleaner offers greater functionality than MSConfig in a number of areas, but let's focus on the its startup cleaning capabilities. It's essentially a more user-friendly version of Microsoft's tool, but with the added benefit of allowing the complete removal of the offending registry keys and shortcuts. It also looks at scheduled tasks, which, if set to run at boot-time, might as well be startup programs, and anything Internet Explorer likes to have running on load.
CCleaner is a good compromise between power and ease-of-use and is the only tool you'll need to keep your list of boot-time apps sparkling. Unless, of course, you're not afraid to delve into the guts of your operating system...
The Hardcore Road: Mark Russinovich's Autoruns
If you have a weak constitution, Autoruns from the now-Microsoft owned Sysinternals is not for you. It goes beyond the basic registry keys and folders where startup apps lurk and exposes pretty much everything that loads automatically when Windows starts, from drivers and services to codecs and network providers.
Busting your operating system is a real possibility with Autoruns, something nigh impossible with CCleaner or MSConfig. Sufficed to say, turning stuff off at random will see you loading a System Restore point faster than you can say "bloatware". The best procedure to follow is to only untick programs and DLLs you're absolutely sure of and even then, don't disable anything that looks like it might be a dependency for something -- you'd be surprised just how interconnected Windows libraries are.
If you haven't cleaned out your startup programs in a while, you might be surprised at what you find in there. Even if you don't reboot often, why burden yourself with cracking open Task Manager and killing unwanted processes every time you reach for Ctrl+Alt+Delete or the Reset button? Take a moment to give it the once-over today and enjoy the warm glow only a quick optimisation can bring.