<prompt> Human: Im 26 and currently have 21k in my 401k after contributing for 2.5 years. Currently contributing 10 towards retirement 6 of my salary 4 company match. No debt, and I will have 6 months expenses saved once I get my tax refund. Trying to figure out how much I will contribute towards retirement going forward.I would also like to save for a down payment on a house or condo, and so Im not sure if I want to increase my retirement contributions. Im just curious where the 15 figure comes from. Why 15 and not 10 or 12 or 20? Also, is this figure 15 including any company matches, or 15 of income ignoring any company matches?  <response>: I assume that 15 was a target that would sustain retirement after a 40ish year working career.There are so many unknowns: future growth, social security, future tax rates, etc. For an eye opening read, you cant beat the math behind early retirement 