If the bitcoin will crashes and drop in $1 i think it would be the right time. I will buy many bitcoin as much as possible. And i will wait the day that bitcoin will rise up again.
Firstly btc prices should not drop below 7-8 k in coming future. As of now it does not really look that it can fall to that extent. But just in case as you said that if it falls 1$ or so then you would buy a lot then it would be time where actually btc will never going to make up or will rise back again.