[sophacles]

This is why all the retirement advice is to regularly contribute - Smaller amounts monthly (or even more frequently) works way better than only doing so when you're flush. The key to this is not spending all the dollars you make on your present lifestyle, but setting aside some percentage for investment from every paycheck. This means you'll be buying in the down times too, where everything is on sale.

Of course it also means accepting a lower spending rate in one's life.