If it reaches to $1000 then it would be wise decision to sell without waiting for anything. And in future if prices goes down will prefer to buy it again.. It can prove to be worst decision if I don't sell it if it reaches $1000 and make profit out of it.
That would only work assuming price movement will follow previous pattern (pump to >$1000 then down again). But if BTC gets mass adoption and price stabilise at well above $1k, then you'll have 2 options: stay away from bitcoin or buy back at loss.
Also if, hypothetically, you'll see massive rally with $100 daily increase, I can guarantee that you wouldn't sell all at $1k, you'd definitely want to see how high can it go.