So can removing unused system components such as screen savers, preference panes for System Preferences and Dashboard widgets. Since your Mac needs to load many of these items at start-up/log-in or when launching Dashboard, you can see performance as well as space-saving gains by trimming down the add-ons that you don't use.
System components are typically stored in the Library folder in your home folder (if installed only for your user account) or at the root level of your hard drive (if installed for all users). A similar set of items that take up space is unused printer drivers, though these are more safely and easily removed using the Print Therapy utility (US$30) than by hand for most users.
In addition to removing the actual application and component files, you should remove the supporting files and preferences files. These can often end up taking up more space than the application itself. Applications typically create support files in the Library/Application Support folder in your home folder or at the root level of your hard drive, where they store a variety of different files that are needed to implement functionality. (iWeb, for example, stores every Web page and related file that you create in this folder, which can take up huge amounts of space.) Preferences files rarely take up as much space but are worth removing as well.
Some applications also create folders at other locations in the Library folder(s). So, taking a quick look for anything that looks specific to a deleted application can help eliminate space as well.
If performing this process by hand seems a little too complex or time-consuming, AppZapper (US$13; free trial) is a great inexpensive utility that ensures that when you delete an application, all of its supporting files go with it.
AppZapper can be used to locate and remove third-party preferences panes and Dashboard Widgets as well.
6. Reduce log-in items
This tip takes on performance rather than disk space. You can often speed up Leopard's initial log-in time, as well as some of its overall performance, by limiting the number of Login items.
Login items, which can include applications and helper processes for system components and apps, launch automatically and typically continue to run in the background while you're working. Often log-in items are installed along with an application without your knowledge. Some of these may be needed for the application to function properly, but not all.