I think that setting conservative “sleep” settings can bridge the divide between power/wear-n-tear and usefulness. Set it so that 30 minutes of non-use sleeps the whole system, and that 10 minutes sleeps the display. Or even briefer! You don’t have to “close up shop,” as it were- saving and cleaning up everything.
Macs run maintenance routines at 12 am (clearing temporary files and cache), but I think that they do them during the day if they’re off at midnight.
@mea was right about big files- for torrents or even massive, many-gigabyte local transfers can take hours and hours.
Also, I have a DVR peripheral, so my computer wakes up to record.