Depends on the person. I have one customer that had me restore his '71 145S to like new condition 8 years ago, and he's brought it back every year or two since then for upkeep. He bought it new, and traveled all over the world with it. (Air Force Lt. Co.) It was either that car or no more 140's for him. I've refinished a few others for customers, but none to that extant though. I've also restored my '71 142E, and mildly customized it in the process. My dad still uses his '70 144S to go to work every day. I have several others that I've restored to daily driver status for my own use. The '72 144E that I customized with 240 doors, virgo wheels, sway bars, etc. is relatively nice. Body needs to be refinished after a close call with a gaurd rail on icy roads, parking lot fender bender, and lots of road salt.
To me the 140 is the ultimate usable vintage car. It's old enough to have real character, and be easily worked on. Yet it also has modern performace in terms of HP and brakes that it can get on just fine in every day traffic.

-Nick