Personally, my wallet has staked for several days, which equal to more than one week, and different addresses in my wallet got different wave of staking rewards.
The period between two continuous rewards are almost the same for addresses with the same staking weights (by owning the same amount of Solaris).
By the way, as the Solaris roadmap shown, the txbit.io exchange might be released in the fourth quarter of the year 2018. I hope that the exchange will be launched a bit sooner, might be in the third quarter this year.
Best wishes for all.