My three cents.
* Unless you're very sure, do not buy leveraged ETFs esp. if you have cash. There is no free lunch.
* Market timing in the long run works. You exit at the better moment (do not follow some experts told you to exit in 2009 in a best seller). My simple chart worked for the last two major plunges. Nothing is perfect as there could be false signals. If it works perfectly, there will be no poor folks by buying my $10 book. Check out the following link and decide it yourself.
* It is a common mis concept of holding cash. Of course it cannot beat inflation. However, if the market is risky, do you want to see your stocks falling like 50% or your cash losing to the annual inflation about 3%? If you do not have cash, how can you buy when the market recovers?