Yes - that is not a bad algorithm - or asset allocation - up from the 100 that folks used to use. However - many other factors - assuming a 30-40 year old has a relatively secure job - a good budget - and good emergency fund - 3-6 months worth of living expenses - then why use any bonds at all since over time - 10 years or more equities will always out perform bonds. Conversely - for a 60 year old in early retirement - poor health - 60% equities may be too aggressive. So - one size does not fit all. Even a 70 year old retiree that uses the bucket strategy having several years of retirement plan distributions in cash or near cash - could be more aggressive than otherwise indicated. For someone eking out an existence on Social Insecurity with few assets - perhaps could be in 100% cash or near cash - so again depends upon numerous variables. To get additional insights - MoneyWise recommended Sound Mind Investing - has a great newsletter - tools guidance on asset allocation - and on page 11 of each monthly newsletter has a table of recommended asset allocation where the allocation is based not on some arbitrary number but the number of years until retirement - check them out.