I currently have 21 Nikon Speedlights. Only 1 currently does not work. An SB-600 with a blown tube. I have flashes going back to the 80's that still work. But I take care of my flashes. Even if the older one's don't get used very often. They get checked and fired off every 3 months. When I do large architectural jobs they are all put to work with radio triggers. The older ones have longer recycle times. But they are not used for fast shooting situations either. I have SB-700 that I carry with me for my travel camera (D3300). Really a decent flash. Had it 2-3 years now. No issues with it at all. I have heard lots of good reviews about the Yongnuo flashes. They are about 1/3 to 1/4 of Nikon flashes. And some models have direct Nikon communications. Many people say they are good. But they are still fairly new to the market.