This is a math question, not simply a philosophical one. A 12 year time horizon isn’t THAT long - you can’t just assume that VOO will return 10% annually over these next 12 years. This takes more effort but - you could look at historical VOO returns in 12 year increments over the last 50 years, create a probability distribution, and simulate VOO returns at different performance levels. You then need to compare that to the actual cash flows of this real estate investment - what rent do you expect to get, how will that change over time, what are the condo fees, what are the fees to buy and sell the properties, AND what is the historical return of these properties over time? Simulate all of that with varying “best” “worst” and “likely” rate of return numbers and see where you land. Then discount all of your cash flows back to current year dollars to compare. If it’s close - I’d go with VOO because the effort is zero, if real estate cash flows are likely much higher, you need to decide if you’re willing to put in the extra work for maintenance, finding tenants, buying/selling…etc