My eyesight isn't as good as it used to be, so I tend to shy away from 1/72 and even 1/48 scale models. I know that 1/48 in pretty much the standard in aircraft models, and many planes can only be found in that scale.
I have been looking for even larger scales. I have a 1/6 scale Sherman tank I have yet to built, and a 1/72 destroyer, which will be huge when it's done (If I ever get around to building it).