What great responses to this thread and thanks to all. As for myself, I model in HO scale. I am currently building my fourth layout after a long stint at being "armchair" and enjoying this simulator.
I must say this, as much as I love this simulator and will continue to do so, I am always drawn back to the tangible aspect of model railroading. I enjoy building the structures, tuning and detailing the rolling stock, weathering, building bench work, and electronics/wiring.
I too, like others, have found that over time my eye sight is not what it used to be and this has spurred me to seek out an optometrist. My hands are also not as steady as they used to be. To me though...there is nothing that can replace being able to hold things in my hand, build things, or the interaction with club members. However the endless amount of space, the DLS and what it has to offer, interactive industries, and the low cost will continually keep me returning to this train simulator.
I was , but the choice came down to a model railroad or a wood shop and the shop won and the railroad went into boxes which I still have.
I am also a wood worker both as a hobbyist and part time living. It's great to be able to incorporate my wood working into model railroading. My bench work and switch panels are "fine furniture" quality. I have been fortunate to maintain my entire basement for woodworking and use a spare bedroom for a layout. At least you have everything packed in boxes so you still retain that option.