I was watching North Mission Road on ID and this lady used a "technique" that she made up where she sniffs the bones and if she gets any odor of decomp then the person likely died in the last 2 years. If no odor, then they passed greater than 2 years ago. Obviously not super scientific, but it gives her some idea and I guess with all her experience this is how she came up with it. This was just a snippet during the show so I may not have all the details, but it kind of gives you some frame of reference. I would think the body will still smell, however it does dissipate. I think it smells the most in the weeks following death, as the flesh is actively decomposing. The third or 4th day is when the body usually bloats and the gases that build up cause it to explode, which is something I wouldn't want to be around for and what I would imagine occurs during the worst of the smell. So the lady that works at NMR's technique indicates the bones would probably hold some odor for a year or 2, however light of an odor.