There is a great chart in this article showing how saving $500 per month (at a 7% rate of return) will enhance your retirement's success rate. At $500 per month you are only saving $6,000 per year (far below what your 401k plan allows). For example (in calendar year 2018):

Employees under age 50 can save up to $18,500 per yer in their employer sponsored 401k plan, plus any employer matches, plus up to $5,500 in an IRA; or
Employees over age 50 can save up to $18,500 per yer in their employer sponsored 401k plan, plus a $6,000 401k catch-up contribution, plus any employer matches, plus up to $5,500 in an IRA, plus a $1,000 IRA catch-up contribution.

Notably, even saving at $500 per month from the age of 25 (at a 7% rate of return), one can amass nearly $1.7M by age 70 (per the article). Not a bad a result for a small (noting that everything is relative) sacrifice! However, start at the age of 50 and you will only accrue $246K . . . it pays to help youself and your children to start saving early for retirment!