How to check the life left in SSD or the medium's wear level?
In your first example, what I think you are referring to is the "Media Wearout Indicator" on Intel drives, which is attribute 233. Yes, it has a range of 0-100, with 100 being a brand new, unused drive, and 0 being completely worn out. According to your ouptut, this field doesn't seem to exist.
In your second example, please read the official docs about SSD_Life_Left. Per that page:
The RAW value of this attribute is always 0 and has no meaning. Check the normalized VALUE instead. It starts at 100 and indicates the approximate percentage of SDD life left. It typically decreases when Flash blocks are marked as bad, see the RAW value of Retired_Block_Count
It's really important that you fully understand what smartctl(8) is saying, and not making assumptions. Unfortunately, the S.M.A.R.T. tools aren't always up to date with the latest SSDs and their attributes. As such, there isn't always a clean way to tell how many times the chips have been written to. Best you can do, is look at the "Power_On_Hours", which in your case is "6568", determine your average disk utilization, and average it out.
You should be able to lookup your drive specs, and determine the process used to make the chips. 32nm process chips will have a longer write endurance than 24nm process chips. However, it seems that "on average", you could probably expect about 3,000 to 4,000 writes, with a minimum of 1,000 and a max of 6,000. So, if you have a 64GB SSD, then you should expect somewhere in the neighborhood of a total of 192TB to 256TB written to the SSD, assuming wear leveling.
As an example, if you're sustaining a utilization of say 11 KBps to your drive, then you could expect to see about 40 MB written per hour. At 6568 powered on hours, you've written roughly 260 GB to disk. Knowing that you could probably sustain about 200 TB of total writes, before failure, you have about 600 years before failure due to wearing out the chips. Your disk will likely fail due to worn out capacitors or voltage regulation.
For Samsung SSDs, check SMART attribute 177 (Wear Leveling Count).
ID # 177 Wear Leveling Count
This attribute represents the number of media program and erase operations (the number of times a block has been erased). This value is directly related to the lifetime of the SSD. The raw value of this attribute shows the total count of P/E Cycles.
Source: http://www.samsung.com/global/business/semiconductor/minisite/SSD/M2M/download/07_Communicating_With_Your_SSD.pdf
The wear level indicator starts at 100 and decreases linearly down to 1 from what I can tell. At 1 the drive will have exceeded all of its rated p/e cycles, but in reality the drive's total endurance can significantly exceed that value.
Source: http://www.anandtech.com/show/7173/samsung-ssd-840-evo-review-120gb-250gb-500gb-750gb-1tb-models-tested/3
I would suggest you take that last statement about exceeding that value with a grain of salt.
If you don't have an Intel-brand SSD: Be careful!! I have a Samsung SSD, and I was totally misled by erroneous attribute labeling by smartmontools /smartctl. If you have anything except Intel -- you may find my story of (inane) pain at https://askubuntu.com/a/460463/65722 helpful.
May your ratio of information-quality to time-spent-digging be better than mine!