The S.M.A.R.T. system built into all modern hard drives has been known since the times of hard disk drives. It keeps monitoring various parameters of the drive technical condition and gives it in relative numbers. As soon as the values of the parameters get below the critical level, the drive is considered unreliable and the manufacturer recommends replacing it. However, in practice the drive may continue to function normally and manufacturers themselves say that SMART is rather a recommendation than an exact prediction.

Unlike the case with hard disk drives, everything is more certain in the world of SSDs. The lifetime of flash memory, on which SSDs are based, is limited to 10 000 times of writing (simply speaking). All drives contain firmware making sure that all memory cells are used evenly and monitors how many times data is written to them and how much time there is left for the SSD. Finally, it is this data that the drive firmware summarizes in one of the S.M.A.R.T. parameters called SSD Life Left or Media wear out indicator – and it is this parameter that SSDLife shows in a convenient and understandable way.

So, we know the exact lifetime capacity of an SSD and can monitor changes in it. However, most of the drives also show data about written and/or read information in their S.M.A.R.T. parameters.

Note: by the way, some manufacturers give the total amount of data written to the drive as one of the drive lifetime indicators. For example, Intel guarantees that the total of about 37 TB of data will be written to X25-M drives (20 GB per day for 5 years: “The drive will have a minimum of 5 years of useful life under typical client workloads with up to 20 GB host writes per day.”).

It’s a simple mathematical problem: in order to calculate it at once, we need to know at least the date when you wrote data to the drive the first time, but unfortunately, drives do not provide this information. That is why we need some time after the first launch of SSDLife to monitor how intensively you use your SSD in order to determine its average load. And as soon as we can calculate the approximate average amount of data written to the drive per day, we will be able to determine the time it will take you to use the entire lifetime capacity of the drive, which means we will be able to calculate the date when the lifetime of the SSD will be over. Of course, this date will keep changing depending on how the intensity of the drive usage changes.

In some cases, the estimated lifetime can change dramatically. It happens if the amount of data written to the drive quickly increases. For example, if you install some large game. But do not worry, literally in a couple of days SSDLife will figure out that it was a one-time upsurge and the disk is back to its normal amounts of written data so it will correct the estimated lifetime.