It all depemds on what your goals are and what ypu start with. If ypu have a million dollars and want to get your stack up to 2 million i dont think you need 7 to 10 years. But if you start with a thousand dollars and want to grow it to a million you might need longer. Long term is good but you need to outline your goals to see how long you think you should hold your position for.
We could assume that most of us here are average joe investor, so we don't have that kind of millions to invest in the beginning. Majority could have been doing DCA for at little as $20-$100 and that could be a good start and then look at the bigger picture.
So for sure that will be our goal here, at least the majority of us who doesn't have big capital to start. It's a slow and painstakingly process, and we need dedication in order to be successful in the future. DCA is perfect strategy for that.