[mathgeek]

Only if you are far enough from retirement, or have enough assets, that you can handle the risk. Same as any other period.

[DailyHN]

20+ years to retirement

[dbancajas]

+ you are sure your job is secure enough that you won't need the extra cash as cushion before being able to find another job.

[enraged_camel]

This shouldn't matter at all, since there are huge penalties associated with taking money out of your retirement funds before you're 59 and a half years old.

If your job is not secure, you should account for that by increasing your emergency funds (typically a savings or money market account).

[T-hawk]

There's not always penalties. Look up what's called the Section 72(t) distribution. This is a "retire early" option, where you can start taking a monthly distribution at any age, without penalty (income tax still applies), as long as you maintain that distribution for the longer of five years or until age 59.5.

[lawn]

For reference the typical advice for risky allocations is at least 10 years, but longer is better.