As the title says, would you buy hard disk defragmenting software or are you fine sticking with free defragmenting tools such as Windows disk defragmenter ? Paid software, such as O&O Defrag, is faster and has more features, such as doing defragmentation work in the background when system is not under load, defragmenting multiple hard drives simultaneously and has added built-in utilities, such as registry cleaning and optimization tools. Personally, I use the defragmenter that comes with Windows. It's not the fastest, but it gets the job done for me and I didn't see any performance increases by using other software.
As much as possible, I don't buy software because the license is very expensive. And since there are lots of freeware in the internet, I just persevere in searching, downloading and installing. With my anti-virus, it is the free version of Avast and our laptop is running with AVG. For defragmenting, I actually do not defragment my hard disks because it is very time consuming. Hard disks are large now so there's not much need for defragmenting software for me.
Honestly it really depends on the price of the software and if it has any good reviews. I usually don't have to use such software as I tend to stick with using antiviruses and just do system restores. If anything I could just use products like Ccleaner or malwarebytes, both might get the job done just as good.
Defragmenting can be done without a program. However, some people don't want to bother with it. In that case, as we know, there are programs which automate things. Anyway, in my case, I just use an auto-program, System Mechanic, to clean up and defragment things. Are you sure that's a good idea?
As @Jason76 pointed out, that may not be a good idea. SSDs should never be defragmented, but hard disks absolutely should be defragmented, considering how they write and read data. I think the problem even gets worse if you have a large disk and then install/save on it a ton of stuff, your PC can slow down significantly. It is time consuming, but you can just let it defragment while you're not doing anything on the PC, or just let it defragment overnight while you sleep. It should only be done occasionally anyway.
I am using software named ultradefrag. And it works for the SSD. And it seems to be good enough on the defragmentation of the files and the data. You can see that for recuva's defraglr. It can be really good for the format also. I think ultra defraf is lot better on that side. I'd be surely be using it in such case. It seems to be good enough.
I think all defragmenting software can technically defragment SSD's, but you should NEVER do so! First of all, it does absolutely nothing for performance. SSD's read data much faster than a hard drive and in a different way, that is, they read data electronically instead of mechanically. More importantly, SSDs have a limited amount of read/write cycles, and you're actually wasting these and thus shortening the lifespan if you're defragmenting them, for no good reason.