figuring out when to buy is very subjective. There isn't a certified time to buy. Just like any other crypto, you make a decision yourself. What is seen as a need currently is the power redistribution from the top 1% owning >95% of steem and the need to lure in new investors. Both have high chances of happening when Steem value is low. How low? Nobody knows but definitely lower than it is now.

Track the graphs on Poloniex, coinmarketcap etc. There are also many financial analyses posted around so Search for those too.