About RAM

Now it costs 4 GB, I'm buying in addition to save myself from friezes, the question is in the motherboard 2 slots, if I buy 4 then 8 will be the limit, I will take 8 will be 12 for the future, 8 is not enough ??? They just say that GTA, the operative tomb rider flies away for 7-8 GB. What do you think?