Should I buy a single stick of RAM or a dual-channel kit for a Ryzen build?

Buy the 2x8GB 3200MHz kit now. Ryzen is sensitive to memory speed and dual-channel configuration; running one stick in single-channel mode costs 10-20% gaming performance. Finding the exact same stick later is unreliable and mixing sticks can cause instability. Spend the extra $30–40 now to avoid opening the case again.