WARNING: I rarely write such a short piece but I've been answering the same question all day. Please upvote so that I don't have to repeat myself. :-)
Okay, there are a lot of new people here. I thought it would be good for all to revisit an old article on the topic that one of Steemit Top Author wrote ( 
It would be a good idea for you, if you are new, to read his other posts too.
GO TO: https://steemit.com/steem/@donkeypong/would-albert-power-up-you-need-a-long-term-plan-also to understand STEEMPOWER and decide how much you should power up.
SteemON
EDIT: This new article from
https://steemit.com/steemit/@donkeypong/come-for-the-steem-stay-for-the-steem-power-this-is-getting-unfair-for-bitcoin-ethereum-reddit-and-facebook
EDIT[2]: Meet 12 Steem Superheroes, The Brave Men and Women Powering Up Bigtime
https://steemit.com/steemit/@pfunk/meet-10-steem-superheroes-the-brave-men-and-women-powering-up-bigtime