If you are the type of person who likes to sample and remove programs from your computer very often, you are probably familiar with system crashes and you also probably badly need a registry cleaner. You should realize that it is the way you dizzily install and uninstall programs that is causing your system to get flat feet and eventually to fall on its face. Every application you load into your system gets its corresponding slot in the system registry. It fills its slot with the key-value pairs that it will need to run and continue running.
The trouble these poses for people who are restless about their applications is that those entries are deleted when the application is uninstalled. Unless you have a registry cleaner, long after a program has disappeared from your drives, those entries remain. They are not dead entries, but they are more like undead monsters that eat up your memory and overwork your cpu. They all need to be scanned when your cpu looks up key-value pairs to run a program. Registry cleaners identify and remove invalid key-value pairs and prevent system overload which can ever lead to a crash.
Registry cleaners ferret out the ghosts in the registry and delete them. Vice versa, they can also identify whether you are missing some entries in the registry. The better ones allow you to make a backup of the system before the actual scan is done so that in the event of failure causing system handicap, you may restore the original settings. That is also the reason why the better registry cleaners are safe to use often.
People who are experts at system configuration sometimes fix their registries manually but that is not an option for average users. However, some registry cleaners enable you to perform manual removal of entries. They will first present you with a list of data that can be safely deleted and the choice is yours whether to do so or not. In this way, you can keep configurations that you intend to use in the future. Another feature included in some registry cleaners is deletion of shortcuts and references in the Path variable of windows to non-persistent programs. This speeds up both your computer's performance and as well as your own.
So if your are the type of person who
1. simply has to try out every new program and are there before probably always uninstalling old ones to make room for new ones,
2. can not get your first installation right the first time (it does happen),
3. has a computer that everyone else else in the house uses and installs programs into
Please do what is best for you and get yourself a good registry cleaner, one that allows you to backup before scanning the registry, one with which you can perform manual scanning and on which you know you can rarely. You simply have to do your comparative research on the internet. Look up prices, the features included in the software and customer product reviews. You might also want to try the free system scans offered by some registry cleaner sellers.