Is it better to leave a PC on 24/7 rather than turning off at night then rebooting each day?
No windows needs a reboot every now and again to refresh registry settings and various other things.
EG just burnt a DVD will not auto play or show files in explorer but will work perfectly after a reboot.
Does running numerous daily scans for spyware/trojans/virus & regular optimizing wear a hard drive out quicker in the long run?
Only run a scan very couple of days most decent antipy / antivirus has active scanning in system tray.
Perhaps only need to scan if been on dubious sites such as ringtones, screensavers etc.