We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Is weight training to muscle failure a good idea? It depends.
With smaller muscle groups, we all commonly train to failure, or close to it, but more often just to the point of excess pain. I'm thinking of examples like curls, forearm exercises, pushups, pullups, cable pull downs and push downs, rows. In fact, many gym machines (which I rarely use) isolate smaller muscle groups in ways that lend themselves to high-rep muscle endurance work (ie 15-20 reps).
With the powerlifts, we do not recommend lifting to failure very often. Just occasionally, to beat the heck out of yourself, and with a spotter. Rule of thumb with powerlifts is mostly to do the number of reps you can manage to accomplish 4-8 times in a row. If you can, for example, deadlift a weight 12 times, raise the weight right away to get down to 6-8 reps for each set.
As a 75 YO man who has actively exercised all his life (weight lifting, jogging, running, sports) My advice is to exercise moderately. If you are training for the Olympics or some other venue where some kind of absolute fitness/strength is essential to winning AND you are willing to suffer the consequences then go for it. Otherwise consider that you can and likely will hurt yourself with excessive or over vigorous exercise. AND that you will also likely suffer consequences in old age that were not noticeable when you were 20 something.
I will also offer this piece of advice that will surely not set well with many who exercise; the 20 something (or 30 something) hunk at the local gym who is a trainer only knows what it is like to exercise in his/her prime. They are almost clueless of what they can expect when they are 60 or older. They think that pushing yourself to the limit everyday is good and moderation is a sign of weakness. And of course they are "experts" so we accept what they say as truth. When in fact they haven't yet lived long enough to know the truth.
Moderation my friend and if it hurts that's your bodies way of telling you to stop.
My college girlfriend’s cousin was a bodybuilder who won Mr. Alabama. He had, of course, an amazing physique.
He was a member of several gyms in Birmingham and I would occasionally see him working out at my gym. He used moderate weight, moderate reps, with extremely strict form. You never saw him grunting or struggling and straining with his last couple of reps. His workouts were calm and workmanlike. I asked him once about why he worked out with lighter weights and he said “Stimulate, don’t incinerate.” He said he got everything he needed from moderate weight without the downsides of lifting heavy and going to failure, and that he recovered much more quickly by not going to failure and always being so sore.
As I’ve gotten older I have adopted his philosophy with great results and a healthier, more athletic body. Training hard is great, but training smart is just as necessary.