It really depends on how hard you push your pc. Some people can do some hardcore Editing/Rendering that even maxes out sets of 64gbs RAM. Best way for you to come to a conclusion is to make it youself whether to get more RAM or not.
Stay with your 8gb for now and keep track of it the next time you do some of your most intense stuff and if it gets near maxed or does get maxed then go for the upgrade if not you should be fine
Well I haven't bought it yet, and I'm afraid if I begin to edit a lot more in the future I will be limited to 16gb, with two 4gb RAM. I don't want to just throw away the 8gb if I want to upgrade to have 32 gb or something like that.