"No pain, no gain"? It's catchy, but in actuality not an ideal approach to training. A better saying, albeit less catchy, might be “Do Train, Don't Strain"
Many people who train believe the only way to get results is by leaving the gym completely exhausted and sore. While you absolutely want to work out with intensity, it is far more important to focus on improved performance and technique than on achieving complete fatigue. Of course you should be temporarily exhausted post-workout, but fatigue is something more... the beginning of potential injury.
Your body is talking to you - listen to it.
Get to know your limits and don't believe the hype
Go for intense activity, but make each movement count and at the end of your workout day be sure to leave a little gas in the tank for recovery. This becomes even more applicable the older you get.
Your body is talking to you - listen to it. Get to know your limits and don't believe the hype - if at the end of your workout you're vomiting or limping it doesn't mean you've had a great workout, it means you've overdone it and wreaked havoc on your body.
What do you have to say about it?