On a RHEL course many years ago the instructor said (semi-seriously/jokingly) that "rebooting is a sign of weakness", the gist being that there is a fair bit you can change on the fly in Linux. However he also pointed out that's all well and good until the server reboots... so it's best to make changes permanent. And as part of the RHEL certification exams they'll reboot servers to make sure.
Meanwhile there are some people who seem to think that uptime is a bad thing and insist on "maintenance reboots", which to me are the work of the devil and usually cause more problems than they (attempt to) solve. If there's a problem on a Linux box that requires frequent reboots to "fix" (eg pospone till the next time) then looking into the problem is probably a better idea than rebooting to mask it.