It will last at least three years, unless you have an extraordinary usage.

Assuming that the V+100 is based on 25nm flash (3,000 program/erase cycles), you get:

3,000 * 120GB = 360,000GB of total writes over its lifetime

Let's assume that the super aggressive garbage collection is rather bad and consumes 2/3 of the writes, leaving you with only 120,000GB of writes to be used as you wish. You need to write 108GB every single day to exhaust the SSD by the end of its third year. I believe it is safe to say you don't need to worry about its lifespan at all and may expect much more than a three year lifespan without changing your normal usage behaviour.

On a side note and for reference, Anand (of AnandTech) observes that he used an average of 7GB of writes per day and that he was the heaviest writer within the people of AnandTech.

Still happen after reformating OS
Could be due to hardware or software initialization at startup.