How important is it to keep the Windows registry defragmented and clean?

Glary Utilities FTW! :D

It's important to use good, trusted, utilities, don't just download whatever you find from doing a search on the Internet, because there is A LOT of malicious software out there guys...

The registry, after installing and un-installing software, updates, etc, becomes bloated with old an unneeded entries, also sometimes, when registry can become corrupt, some programs ca n uncorrupt them to an extent.

Furthermore the best solution is to build your OS, install all the software you want on the machine, perform all the necessary updates, then BACK IT UP...

Because a backup is the best solution you have, no need to go through hours of worrying, fixing, undoing the bad things that can happen, just restore & it's back to where it was when you first installed everything and updated it...

To properly use backups, you will want to keep all of your media and files you have added, save your bookmarks and settings on to another Hard Drive (preferably a large one), this way when you restore you don't have to keep moving stuff, it's all where you put it..

A restore will not take you more than 20 minutes if you did it correctly. Complete computer setup is the key, and as time goes on, you can make new backups to save your self time in the restore. But never delete the first main backup!

There are multiple different programs that can help you do this, and in Windows Vista & Windows 7 Ultimate allows you to make Back Ups as well, just make a Windows Repair Disc from Windows and your good to go! Spotmau & Acronis are great for backups too.

It's important to keep your registry backed up as well, in case something goes wrong with it, or it becomes infected with malware, viruses, etc.. ERUNT can do this for you, or even windows itself.

I'm a tweaker, if I can speed up my system by a milisecond, I'll try to do that. It's a hobby really; that being said, I clean and defrag my registry every week. (Automated task, TuneUp Utilities) and it does indeed improve the speed of my computer just a little bit. For me, totally worth it, for other people, maybe not. I clean my dads computer (inside out) once a year, and he doesn't notice any difference. Depends on the person I guess.

To be truthful about it, it's really not a necessity. The only time one should ever worry about cleaning/defragging the registry is if they are someone who installs/uninstalls many things on a frequent basis.

On my laptop when I still used XP before switching to 7, I used RegScrub XP. This helped a "little" but I didn't seem to notice much of any kind of "improvement". The only time I ever ran it was right after I uninstalled any software, so that any remaining "traces" of that program were deleted. Other than that, I can honestly say that I didn't see any type of "speed up" or "improvement" in the performance.

I actually have a page bookmarked in my favorites from a year ago or so concerning almost this very topic. I will quote one of the posts:

"The Windows registry is a massive database of almost every setting imaginable for every application on your system. It only makes sense that cleaning it out would improve performance, right? Sadly it's just a marketing gimmick designed to sell registry cleaner products, as the reality is quite different... registry cleaners only remove a very small number of unused keys, which won't help performance when you consider the hundreds of thousands of keys in the registry. This isn't to say they are completely useless, of course. I'd still recommend cleaning the registry when you are trying to troubleshoot a problem caused by uninstalling buggy software that leaves entries behind, but even then you should be very careful to use a reputable application like previously mentioned CCleaner and review the entries before deleting anything."