I would hope out of 17 years you'd have more ups than downs and just a general inflation trend upwards.  Great post above showing how most of these people don't have a clue and just spit the same crap out every year hoping no one goes back and looks at their history.  I remember a lot of "experts" telling everyone to sell every cow you owned and go to calves in '12.  Both went up but if you were in cows you were a lot better off when it fell, as long as you didn't buy all your cows around '14 and you have to buy calves every year if you want to sell any.  Don't have to buy cows every year.

If you really want to get killed try and time a falling market.