Well, what is your goal? The best bang for your buck in terms of time spent is weight training, just do Starting Strength, Mark Rippetoe, and once you’ve maxed that out, go for maintenance. Three hours a week. But cardio exercise is probably near as good and might be just as good for most purposes except maintaining muscle mass as you age. For that just do a Couch to 5K programme and then run regularly. If you feel like running more than three times a week do it. If you feel like running longer distances, do it. Or don’t.
By far the biggest difference is between the unfit and the moderately fit. Just start slow, take it easy and do something. Doing yoga four hours a week beats no exercise by a lot.
531 Forever for a person willing to read, and read again, for someone that wants a framework for resistance training+conditioning that they can use for the rest of their life.
Paul Kelso's Powerlifting Basics, Texas-Style: The Adventures of Lope Delk for the person that want a few different routines that are more geared towards strength.
If I was a person starting anew though I'd place less emphasis on strength initially and use a more varied set of exercises. My personal recommendation would be John Meadow's Baby Groot, it is written so well it could just about be understood by a computer program. Few, if any, ambiguities. Helpful examples. And video links to each exercise.
That could all be true. I wouldn’t know. But SS is absolutely sufficient to get all your beginner gains and then switch to maintenance which would get you 80% of the gains for 20% of the effort. Don’t let the perfect be the enemy of the good. Better any plan to become fit that’s not actively harmful, executed, than someone putting it off to find the perfect plan.
By far the biggest difference is between the unfit and the moderately fit. Just start slow, take it easy and do something. Doing yoga four hours a week beats no exercise by a lot.