I really enjoy reading the forum, some of the discussions have taught me quite a bit. So, a big thank you is in order. I have a bit of a dilemma and I was wondering if someone could chime in. I've recently come to the conclusion that my D3S is getting a little long in the tooth and I am at odds as to what to do. One thing I have learned from this forum is that glass is the best investment and bodies come and go. Don't get me wrong, I love my D3S, it is the camera that got me to switch from Canon; I had a 7D and I absolutely hated it. After playing with the D3s at camera store as something as a far fetched curiosity I fell in love with the switches and the extent of the manual controls. So I switched to Nikon. I have been shooting the D3s for four years now with no issues, but I am afraid it will be soon worth nothing and I will have to start all over again out of pocket. I shoot less paid work now and the D3s and my 70-200 2.8 II are far too heavy and painful after a full day's shoot or outing. I was thinking about a Df, but the thought of a single card slot scares me from using it as my only option for some of the paid work I still do. My next thought was a D810 and I was hoping to trade straight up, and trade my 70-200 2.8 and a 24 2.8D for a 70-200 f4 and 20 1.8G. It seems that this is not possible. My gear is in like new condition but I'm not exactly sure how to price it. My local camera shop whom I have bought from for years believes the trade isn't too crazy but they are not accepting any used Nikon Gear because there counter is full for a smaller shop. i.e. 200-400, D3x, 70-200 Vr 1. The same shop in another city four hours away offered me 1200$ for 70-200 2.8 II, 150$ for the 24 2.8D and 1900$ for the D3s... is this even close to fair? I am shocked at the idea of trading everything just for the D810, but I'm scared that my D3s will soon be worth nothing and I will be stuck with it till the day it quits. Any thoughts?