The Recovery partition, with a minimal working OS on it, will allow you to reinstall the OS (initiate the install procedure and download the installer from Apple's servers via the net) and/or run Disk Utility on the target partition. If that is all you need to do you are OK. However, that may not be all you need to do if something really bad happens. So backup your data and keep your Application install Disks safe. Many people like to have a cloned HD available as a means to get back up and running quickly.