I always turn electronic devices off when they are not being used, including my computers, and their reliability has always been good.
I even put a plug-in power timer on my two Satellite receivers so they are completely off late night and during the daytime hours when I never watch TV, since they consume near 30W apiece, even if you use the remote to turn then "Off" (which apparently just turns off the video output).
I have a 7-day timer so, for football season, they are naturally turned on earlier on the weekends.