@Kaile I'm worried that holding both VOO and QUAL is just doubling down on the same U.S. large caps. Am I actually diversifying, or am I just increasing my risk if the U.S. market stalls over the next decade? How much overlap is too much?

As a long-term investor, does my 50/50 mix of VOO and QUAL really provide enough diversification beyond large-cap U.S. equities, or should I add mid-caps, international exposure, or quality bonds to balance my risk over the next 10 years?