So guys, I have been following the MMM approach to investing for about 2 years now, ever since coming across the site. I make it a point to avoid any discussion on the topic, but I've always had a reputation for being responsible among friends. Recently, a friend asked how to know how much to save. I told him about the 4% rule and assuming a market return of 7% and said he could do the math and be more or less conservative with the numbers as he saw fit. Another friend was there and just would not accept this kind of thinking... "You can't assume you'll get 7%... When the market crashes, you'll start over... You're irrationally confident in the market..." I really have no idea where to go from there in the discussion. In some sense, he's right. I have no answer for some kind of market-never-recovers scenario. I chose to abort the conversation after coming off very standoffish since from my perspective, he's on shaky ground. I want my friends to be responsible and am happy to share if asked (especially since we are late-20s to early-30s and have time on our side, imo), but I don't know how to positively respond to this kind of critique.
Have you run into this? Do you have any answers? Advice? Is there any point in worrying about friends?