New to Playstation Plus
does all the free stuffs on PS+ accumulate over time?
Yes, it accumulates over time
Meaning the earlier you join, the free stuffs you get on the way will be free to you forever and just keep adding?
If you joined Day 1, and DL'ed everything given away, as long as your subscription is active, you can DL to your hearts desire, you keep adding
Not free forever
What happens if you quit it for two months and come back? Will everything lost?
No, if you quit or subscription runs out, games stop working that were given away during your PS+ subscription
They're are still your DL list, (I think you can even DL them), they won't boot up though
Once you resubscribe, all PS+ content gets pushed up in your DL list as first dibs
So say like me, I've been Day 1 since June 29, 2010, once I finished using my 1 month trial code-a-thon, I'm subbed till January 19th, 2017
Now everything is pushed up, all content PS+ oriented, even stuff I bought afterwards gets pushed down, like 10+ pages down, lawl