Most professional money managers talk about younger folks being more able to hold a higher allocation of volatile assets, due to the ability to take a long term approach. 

I think this is generally bad advice. Younger people have big, important expenditures early in life, too. Tuition. House. Family.  Not to mention, having the fortitude to hold long term takes patience and conviction.  These characteristics are not typically fully matured in younger folks, increasing the likelihood of a sale at the wrong time.  

Instead, the best strategy supporting a high allocation to volatility is hard work and living below your means with low time preference. You can do this at any age. If you don't need or want the liquidity, it is easier to HODL.