There was a game I played that had scheduled events every day of the week. However, it was really demotivating to log in during certain days.
"Why bother progressing Thursday, on Friday I can progress 2x faster". or "Save your money/'gems' until Saturday" so nobody wanted to play all week.
Heck, when these events were more frequent, I remember having stocked up 200 ocarinas in preparation for the surcharge event...then 2 months went by without the event, it was a little demoralizing/frustration inducing sadly.
I'm not saying events are bad, but just that, sometimes the expectation changes player behavior and can become a negative. I wish I could suggest a better/more motivating approach to an event system, however I cannot think of anything. If your event runs so frequently, it may as well be permanent, otherwise, keep them as "special events" and surprises as best you can. Don't make them too powerful, and keep them unique that they change how you play for a day or so.