There may be a lot of wasted space on your Macs. Instead of allowing the Mac’s space to be utilized more efficiently, it is bogged down by unnecessary items. Cleaning up and removing unneeded data frees up space for actual useful things and allows the computer to perform better.
Xslimmer is “your Mac, on a Diet!”. It allows you to remove unnecessary code and languages, and has also been known to increase loading times of different applications. In addition, some currently used applications may also be reduced, as to be more space efficient.
A try out version is also available, allowing to use up to 50 MB of freed up space. You may find more information at Xslimmer and their blog