Do I really Need

I have just purchased two carbon rim wheels for my bike. It was suggested that I also purchase the special brake pads. Is this really necessary? Will the standard shimano pads work ok?

Standard Shimano pads are fine (I use them) but remember your wet weather braking performance will be somewhat poor with either compared to alumnium rims. In general, the “carbon specific” pads a re little better but not mandatory. I’ve used both, I have standard Dura-Ace pads on everything now.