Samsung EVO 840 500GB SSD lifespan or estimated usability life ?

I have samsung EVO 840 500GB ssd installed on my desktop. It is actually not mine but my brother's computer where he used to do all such things but now since he is away for higher studies I use his desktop which is mine also. But my brother on phone always asks me to not to store data on SSD drive and store on regular drive only (this desktop has another 1TB WD sata hdd). He says that it will reduce lifespan of SSD drive. Whenever he comes and see stuff on desktop or any big files then gets angry on me. But what is the use of computer if you can't just store file anywhere you want ? Why he is so paranoid ?

What is the actual life of 500 GB 840 EVO ssd drive ? Any idea . ? I want to know why installed SSD when can not use it freely ?

He is actually right but I think you should not worry because average lifespan of any modern SSD is way more than a normal or regular user can outgrow. Still I suggest that avoid storing or downloading big files on SSD. Try to move all non-essential or randomly used files like movies, pictures, games on SATA drive and keep SSD drive for OS only. This way you will get your computer lot faster and still your SSD will work for longer time.

If its Samsung SSD then you can also install "Samsung Magician" software to keep eye on health and lifespan of your SSD drive.