Every time it dips or crashes it's much more likely that it will rebound than never come back. There's an entire nation working non stop to ensure the highest profits and best returns. Theyll make you a slave before they let the market crash permanently. If you think the dollar is going to tank then invest in tangible assets like gold or ammo.
Edit: and while you sit on the sidelines waiting for a crash its going to double and triple while your ammo pile just sits there waiting