There is still a place for failure sets. i like to fail at 2 or 3 reps every now and then. I think my body takes longer to recover these days so I have days when I'll just do 30 minutes of rowing and that is my workout. Then there are days when I'll lift heavy. I like to train body parts but some days I feel a full body workout does me better. Protein shake after workout to start the recovery is essential. And I have to train around my injuries as they come and go. It has been over 4 years since my cancer treatment and I'm still getting over it. It still knocks me around but it doesn't stop me getting in a workout. I just have to work around it. And I am so much better off physically because I have been able to work out. Cheers.