A 35-pass wipe is 100% unnecessary and shouldn't even be included in shredders anymore.
Developers only include it nowadays because there are still ignorant computer users who believe that's the best software method for erasing data on today's drives.
And those clueless folks won't buy an app that's missing that feature, even though it should never be used.
Mr. Gutmann himself later published the following statement about his original paper:
"In the time since this paper was published, some people have treated the 35-pass overwrite technique described in it more as a kind of voodoo incantation to banish evil spirits than the result of a technical analysis of drive encoding techniques. As a result, they advocate applying the voodoo to PRML and EPRML drives even though it will have no more effect than a simple scrubbing with random data. In fact performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes. For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do. As the paper says, "A good scrubbing with random data will do about as well as can be expected". This was true in 1996, and is still true now."
If you're one of those who are still under the voodoo spell of believing you absolutely, unequivocally require 35 passes to erase your porn (sorry, I mean data), then you ought to see a witch doctor to get that spell removed so you can emerge into the modern world where a few random overwrites on a HDD is enough, it's difficult and/or unnecessary to securely delete files an a SSD, and 35 passes is nothing more than ancient technology - like a UNIVAC I computer.
Stellar Data Recovery says:
"SSDs use a different mechanism to store data than mechanical hard drives. When you delete a file on your SSD, a TRIM command is issued to the drive by the operating system. This results in permanent erasure of the file contents from the SSD. Hence, a simple delete operation will clean data off your SSD. You do not require wiping the SSD using disk wipe utilities."
All that said, I won't use any shredder that doesn't offer a 3-pass option, because I feel that three is plenty for most files, and 7 is enough for everything else.
At least if you're only hiding stuff from family or co-workers and not the po-po or feds.
I've been using ShredIt X for years, and it lets you choose from fifteen different number of writes, as well as which pattern
is used, including ones that meet govt. specs.
That's on my Fusion HDD. When I buy a SSD I'll need to reevaluate the necessity of multiple overwrites.