Turn it off at night or session finish.  Otherwise sleep.

Sleep caused issues for me with Sonar, so I never ever put any of my computers into sleep mode.
 
My primary DAW is usually on all the time, as I am home from being disabled - I tend to work for a block of hours until tired or in pain, then will lie down for a couple 2-3 hours, then get back at it, so I just leave everything on.
 
The cost per year for having the computer and monitors on is pretty insignificant - (as noted above in another post), so I don't worry about it.
 
An SSD has no moving parts, so heat would be its principal enemy, and I have liquid cooling and a giant case with loads of fans in an air conditioned environment, so that has never been an issue.  I DO have 5 additional 2 TB HDD's in that chassis, but I use primarily Western Digital Black drives, which are built to a better standard than many other drives, and I normally keep several replacement drives in boxes ready to replace any that fail.
 
I DO shut the laptop off after each Sonar session, and I think that helps its longevity a bit - how much I have no way to know.
 
Bob Bone
 

I can't stand sleep mode.  never have liked it. it never works correctly for me, IDK, maybe I'm just a dumb dog who doesn't understand it?
 
I leave mine running almost all the time.  I shut it down when I'm going to be gone for more than 2 or 3 days.  other than that, it runs.
 
I shut off my mixer and speakers and rack every night, tho.

So far, the main focus seems to be power consumption and moving component wear. There's a much bigger problem with Sleep, Hibernate and never powering down. And that's application memory leaks and little borks that don't BSOD but still mess things up JUST a little bit. You're not just running SONAR; you're running tons of device drivers and services and other assorted crapola. Windows and OS-X and Android and iOS and Linux and ALL of them benefit from a regular clean start. Not necessarily daily, but regularly.
 
Just think of yourself when you're not regular.
 
EDIT: So me? I run mine balls out, no rest for the weary, until I'm done for the day. I then say a prayer to the h/w gods, thanking them for one more day on this old power supply, and shut her down for the night.
 
But that's just me. And I could, and often have been, wrong.

I strongly doubt any device drivers would have memory leaks *especially* if they've passed the Microsoft driver validation test suite.  In fact, if they've passed those tests and have been signed off by M$, then they will not have memory leaks.  However, self-signed drivers which have not been rigorously tested or (more likely) applications may well have leaks.  But to stress the point a bit more, those tests are truly gnarly, anything getting through them is nails.

TheMaartian
So far, the main focus seems to be power consumption and moving component wear. There's a much bigger problem with Sleep, Hibernate and never powering down. And that's application memory leaks and little borks that don't BSOD but still mess things up JUST a little bit. You're not just running SONAR; you're running tons of device drivers and services and other assorted crapola. Windows and OS-X and Android and iOS and Linux and ALL of them benefit from a regular clean start. Not necessarily daily, but regularly.
 
Just think of yourself when you're not regular.
 
EDIT: So me? I run mine balls out, no rest for the weary, until I'm done for the day. I then say a prayer to the h/w gods, thanking them for one more day on this old power supply, and shut her down for the night.
 
But that's just me. And I could, and often have been, wrong.

+1.
 
A rest at the end of the day is good for people and hardware alike.
The few extra seconds it takes to cold start in the morning and shut down at the end of the day should have very little impact on your work flow, but it could definitively extend the life of the computer, not to mention improve system performance at the beginning of the day.
 
I quit trying to use sleep mode a long time ago - 
No doubt it has improved by now, but in my past experience it caused more issues in the long run than it was worth.
 
I treat my computers (laptop & desktop) like all my other electrical equipment, be it the home entertainment center, television, synth rack, keyboards, monitors, etc. When done for the day, they get turned off...

Outside of the occasional power failure, my PC has been on since 2009.  No hibernate or sleep.

Ever been to a server farm? Rows and rows of computers, hundreds of 'em. For the most part, they are only shut down for maintenance. Ever been in a mainframe computer room? Enormous "big iron" systems that fill a warehouse-size space, and might be shut down once a year for maintenance. There are literally millions of computer systems around the world that essentially never shut down. And they run far more critical missions than recording music. They manage the world's internet traffic, as well as cell phones, 911 services, monitoring oil and gas pipelines, nuclear reactors and air traffic control. They pretty much do it 24x7 with only occasional (scheduled) shutdowns.
 
Of course, these are climate-controlled rooms. Power conditioning, air conditioning, humidity regulation, filtered air. They're noisy because there are hundreds or thousands of fans going. Contrast that to your laptop, which has to quietly function in all kinds of environments.
 
Whether you need to shut your computer down or not really depends on the computer (desktop vs laptop, water-cooled vs single fan) and its environment (hot and humid vs. cool and dry, prone to bad power and lightning, conditioned power vs. sharing a circuit with leaf-blowers). Look inside your computer; is it clean or stuffed with dust bunnies? Does the CPU heatsink still allow airflow, or is it clogged with dust? Have you ever even seen the CPU heatsink? Is the PSU intake clogged? How about the air filters on your disk drives? They have to suck in air, too.
 
My own practice is to shut down once a week, and vacuum the case out once a month. I'm more likely to shut a laptop completely off because heat stress is more likely in a laptop. 

EMP=dark ages again?