25mm rims

My Zipp 808FC are wider than that and so's my Enve 6.7's.What do you want to know? Wider rims tend to be more aero and rider better.

I guess I was curious if riders go that wide, as my current wheels are much thinner, and 23cm seemed to be more "standard" now. But this will be my first purchase of new wheels so I'm learning.

I guess you're running 28+ size tires then?

Unfortunately that is not correct.

When paired with wider tires, definitely.

For training I use 53mm tires.
But for racing, 20mm and 23 mm tires.

Most of the wider rims like the Zipp FC and HED plus are aerodynamically designed for a 23mm tire. Best results I have seen on these types of rims, which also seems to be echoed by manufacturer recommendations and pro equipment choices generally tend to be the 23mm up front for aerodynamics, but a wider 25/26mm tire in the rear, where tire width has much less effect on aerodynamics. The wider rear tire will improve rolling resistance, comfort, grip and pinch flat resistance, all of which have tangible effects on overall performance. This being said, rider weight, road/weather conditions etc. all can affect these choices! Never try anything new on race day, always test it out.