Prefer curls (60% body weight max, 3 sets, 10 reps each), straight back an absolute must and push ups (50 to 100), lots safer on the back for geezers.
Throw in walking a mile or two a day and that will keep you in halfa$$ shape :)
What about shoveling snow? Does that count? :)
Only if you use poor form. Done right they are the best exercise, bar none, for strenghening the back. With regard to curls, you are spending a lot of time working a single muscle the size of an orange. (biceps). Close grip chin ups will work your biceps every bit as much as curls as well as working your lats, shoulders, serratus and traps. I do only one or two sets of curls a week and think I'm probably overdoing it at that. Curls are probably the most overused exercise in the gym but everyone thinks that's the key to having big guns like Arnold.