You can clearly see in the screen shots that others have posted when the last run time was. If you let windows manage it, you are likely going to be fine. If you tell it to defrag, trim, and whatever else every day, you are likely going to have problems.
As mentioned, you know if it is working by looking at when it was last done.
As for it being on or off, did you manually disable it? This not something you can accidentally disable by accidentally clicking some button. If you disabled it, unless you have serious black-out periods during which you remain highly functional (I'm talking serious split-personality disorders), disabling it is something you would remember.
So all you need to do as a user to make sure your boot drive remains "optimized" is to make sure you leave plenty of free disk space for Windows to operate freely in.
So how much free disk space is enough? Don't listen to anyone who says you need a certain percentage. Operating systems care about actual numbers, not percentages. The OS, Word, and your favorite game takes up the same amount space regardless if you have a 100GB drive, or a 4TB drive. You will often see something like 30% of the disk. That makes no sense at all. On a 1TB drive (which is almost small these days), that would be 300GB! Windows does not need 300GB of free disk space. On a 4TB that would be wasting over 1TB of valuable disk space!
So how much? That depends. There is no good rule. Any number really is arbitrary. But I have found leaving at least 30GB free seems to be plenty for temp files, the dynamic Page File, and defragging of hard drive. And that seems to be plenty on SSDs for wear leveling and TRIM operations. More is better, however - especially with a SSD. Just remember that modern SSD makers build in "over-provisioning" space just for SSD maintenance/optimization tasks. So if starting to get down near 30GB, I recommend you start looking at ways to free up space, or start shopping around for a bigger drive.
As for people telling you to defrag a SSD, you can not manually defrag a SSD. At the hardware level, when the BIOS detects a drive, the drive itself tells the system if it is an hard drive or a SSD (or CD/DVD, etc.). If a SSD, the system reports that information to the operating system, which then enables and disables certain features and tasks, depending on the type of drive. You can certainly tell Optimize Disk to manually optimize the SSD. But it will not actually defrag the files, as it would on a HD.
As this point, a 1/2 dozen people have told you your drives are being properly optimized by Windows by default. I think enough has been said.
If you're using an SSD, Windows 10 Defrag doesn't actually de-fragment the drive. It only sends a TRIM command to the drive. MS calls this "optimize." Most manufacturer-supplied apps such as Samsung Magician include a real defrag function that optimally spreads data around the physical media (multiple NAND flash chips).
Yes, as I just posted (probably while you were drafting your post) the type drive is seen by the BIOS and the OS uses that information to determine which tasks to perform on each drive type. So if you have a SSD as your boot drive and HDs as your secondary drives, Optimize Disk will run TRIM on the SSD and defrag on the HDs. The user does not have to do a thing.
Yes, as I just posted (probably while you were drafting your post) the type drive is seen by the BIOS and the OS uses that information to determine which tasks to perform on each drive type. So if you have a SSD as your boot drive and HDs as your secondary drives, Optimize Disk will run TRIM on the SSD and defrag on the HDs. The user does not have to do a thing.
Wow! Dude! It really is best to do some homework and/or read through threads to learn what has already been said before joining and posting something that is clearly inaccurate.
Why? This just is not necessary, can increase boot times, and certainly adds unnecessary wear on the drive.
I agree with ED.
Fragmentation occurs when new or modified files are saved to the disk. And it would only occur to those new or modified files (not to existing files that are not modified) - in particular when running low on free space.
If you are constantly (like every day) downloading and installing new programs, uninstalling old programs, modifying lots of personal documents files and more, then maybe this would be beneficial. But most users are not constantly installing new programs or modifying their existing documents. As for the OS itself, yes, Windows Updates typically installs several new files and deletes old files, but that's not every day.
That said, many of us rarely boot our systems. I may go a couple weeks or longer - only booting when a Windows Update requires it. Between those times, I just let it go to sleep. So the Windows default, once a week, would be more efficient than at boot time.
The reason why I ask is it turn on or off or how do I know if it is doing defrag or not is back in the windows 95 and windows 98 days doing defrag would really slow the computer down well it does a scan you cannot use the computer well it does defrag because of lack of multitasking. The hard drive light would flash like crazy. It would be resource hog well it does scan like running Norton AV scan. You would really know if it was doing scan or not .
I do not notice any of this going on or a computer slow down that apps are running in background doing some thing. And hard drive light is not flasking like cracy and slow computer well it does defrag scan.
Wow! Dude! It really is best to do some homework and/or read through threads to learn what has already been said before joining and posting something that is clearly inaccurate.
Defrag is so windows 95.
Let windows 10 do his stuff.
If you own some SSDs they will be "optimised". If you got heavy HDDs windows will not touch them cause there is no need.
Defrag your big HDDs at night if you feel it would give you some hypothetical performances. You may win 10% performance on them, maybe 20% but you will use them more than usual. That's what I believe, maybe I'm wrong, all I can tell is moving files on HDDs use them.
I do follow my own advice and do my homework before posting. Like most people, I don't like to be wrong. And sorry but you do need confirmation because it is not once a month as you claimed. Again, just a tiny bit of homework with Google easily confirms this. You can see for yourself on your own systems by using the screenshots biffzinker included in his post #11. If yours says anything but "Weekly" you or someone using your computers changed the defaults.
I do follow my own advice and do my homework before posting. Like most people, I don't like to be wrong. And sorry but you do need confirmation because it is not once a month as you claimed. Again, just a tiny bit of homework with Google easily confirms this. You can see for yourself on your own systems by using the screenshots biffzinker included in his post #11. If yours says anything but "Weekly" you or someone using your computers changed the defaults.
LOL I do indeed use my own brain and do my own research and experiments. I am just not so arrogant to expect other to believe me just because I say so, or to assume what I think to be true, is. So I verify my facts by researching for corroborating evidence - and include them so other can see for themselves, like the 4 links I included above compared to your 0.
And I am not so naive to assume my own experimentation in my own tiny universe of my shop and decades of experiment is anything more than anecdotal.
Again, read through this thread. I am not the only one who said Windows, by default, defrags once a week.
Now unless you can find corroborating evidence to support your claim, I suggest we move on.
We can't even have a conversation about DEFRAGMENTING without posting dissertations are telling each other we are wrong.
OP
Instead of elaborating on my experience or trying to convince you of my superior intellect on the subject, I will help illustrate your additional questions and remaining uncertainty by simply providing you with screen shots.
These are from my personal system.
First: Defragmentation is just a pretty UI for the defrag.exe. We will get to this in a minute.
As you can see it has an "Optimize" button and by default is set to weekly.
Second: Like I had mentioned this is just a UI frontend for the defrag.exe.
Why is it called "Optimize" ?
How does it handle my HDDs and SSDs?
Lets take a look.
Anything that is scheduled will generally be in the task scheduler.
Yay found it.
As we can see by installation default defrag.exe is ran with the following flags.
-c -h -o (Not zero)
Our handy friend the microsoft docs tells us whats happening.
Reference article for the defrag command, which locates and consolidates fragmented files on local volumes to improve system performance.
docs.microsoft.com
The important bits are the flags that answer most questions. I will elaborate on some of the commands in addition to the MS definition.
-C
Perform the operation on all volumes. (So regardless of type SSD or HDD perform operation on all detected disks)
-H
Run the operation at normal priority (default is low). (Let the default CPU scheduler handle the process, do not run it with precedence over anything (Process) by default)
-O
Perform the proper optimization for each media type. (Defrag the hard drives and trim the SSDs consolidate on VMs perform the correct type of maintenance for each detected disk type)
There you have it. Defrag demystified.
Please no more 3 page explanations about ones credentials or back and fourths. I will consider each after this post totally irrelevant and will delete them.
I do follow my own advice and do my homework before posting. Like most people, I don't like to be wrong. And sorry but you do need confirmation because it is not once a month as you claimed. Again, just a tiny bit of homework with Google easily confirms this. You can see for yourself on your own systems by using the screenshots biffzinker included in his 
