$5 USD is an amazing deal for Steem but anything below that is an absolute STEAL! It is not going much below that ever again! I just picked up some more when it dipped to $4.75 and my aim is to reach 10,000 Steem Power! I think that if you can reach 10,000 Steem Power, you'll be a millionaire within a few years. I truly believe that with SMTs (https://www.smt.steem.io) and the success of them that will come from Steemit's HUGE following, that the price of Steem will reach $100. If you have 10,000 Steem Power at that point, you're a millionaire. I power up with all of my earned SBD except that which I use to promote my posts. I recommend using a similar tactic, with the caveat that I encourage the use of transacting in Steem for goods and services through tools such as 
If the price is $5 or lower, I would heavily consider taking a fair amount out of other investments and holdings and powering up. I won't regret it and I doubt you would either, because I think the fundamentals of this platform and blockchain (from the perspective of looking at it as a business) are killer! I will be buying and powering up whenever I have extra liquid funds until I reach 10,000 Steem Power and then I will keep on going. I love this platform, everything it represents, and I love the future that it is bringing to the people of the world. Only risk what you can afford to lose, but within those bounds, give it your heart! :)
AS ALWAYS, WISHES OF WEALTH AND HEALTH FOR ALL! :)