Linux Application Installs DO NOT Require Rebooting
One of the things that many users moving from the Windows environment, to the Linux environment, have a hard time grasping, is not needing to reboot after installing or updating applications.
The reason for this, is that Linux does a better job of providing that applications are on top of the kernel, and not part of it. It is true that there are many applications that require specific options be built into the kernel. However once the kernel has been built (and booted) with these options, the applications that use them can be installed or removed without requiring the system be rebooted. The application simply attaches to the hooks that are built into the kernel when needed. It then releases those hooks when it exits, or they are no longer needed.
This is advantageous in that most updates do not require getting all the users off, so the system can be rebooted. The only time that booting is required, is when a the kernel is updated, or rebuilt. Periodically rebooting your server is still a good idea, just to give it a clean slate (remove crashed or zombie processes). These reboots can be done at your convenience, however, instead of being demand driven due to the need to update an application.