Fisherman, you're onto something when you talk about risk.
When you're 25 and investing for retirement you have plenty of time to make up for it if you lose money, so you make riskier investments in the hopes of greater reward.
If you're 60 and plan on retiring soon, you have to go much more conservative because you don't have enough time to make up for it if something goes wrong because you'll need it within a few years.
You should decrease investments in stocks and increase bonds and "cash" investments as you get closer to retirement. You need to be more liquid the shorter the timeline.
* The above does not constitute actual financial advice. Always consult a financial advisor about your individual circumstances.