$200 a day can be achieved, for this you need lot of traffic (about 25,000 page views per day) and a healthy/correct CTR & CPC.
Yes, the 25K pageviews must be combined with honest CTR & CPC, and the source of traffic should be 80% from search engines, just to make sure the traffic is somewhat related/interested to your pages content.
Even before reaching $200 a day, we can relax, but starting from $200 there is nothing to worry about and any increase of the daily earnings past $200 is just to make sure to save a little money, planning for worst days ahead.
$200 a day is just $6,000 a month, so that's a good minimum to live in pretty much everywhere.
But since $200 a day doesn't keep the doctor away, we have other things to worry, at least not to be too relaxed about..
A tip if you want is to think about the traffic, how many page views do you currently have daily? How far are you from 25,000? Ways to increase your traffic should be about producing content for the masses, which can be interesting to most people.