<prompt> Human: Im about to turn 30 years old, single, I live in the Bay Area and I make approximately 250k a year. I got a late start on saving for retirement - I have 60k in a 401k, 10k in a IRA and another 40k in a taxable Vanguard account.I know timing the market is a fools errand, but I cant help but think a recessiondownturn is inevitable given that there hasnt been one since I graduated from college.I have been considering recession-proofing my portfolio by moving by Vanguard index funds into bonds, waiting out a downturn and then buying back in to stocks at a later date.Is this really such a bad idea?  <response>: Yes, it truly is a poor idea. Nobody knows for sure when a recession will occur and you could miss out on several bull market years waiting for the recession. 