you can use them long term as long as you are taking breaks in between cycles etc... you cant just stay on them 2-3 years straight bro... you can safely use them long term if you run the proper doses and take the proper time off in between cycles... the great thing about sarms is that you dont need near the time off in between cycles as you do with steroids... so thats a major bonus as well... make sure to check out sarms.forsale for your sarms...
you need breaks in between, remember sarms still are slightly suppressive to your HPTA. if you just took them 3 years straight you would be hurting yourself more than helping.
Run them similar to steroids. Run your cycle and take proper time off in between. You don't need as much time between cycles but staying on for years will really mess up your hpta.
You just need to make sure you are taking the proper resting periods in between cycles. SARMS do not fall into that time on = time off category like steroids but you still always want to give your body a break when using ped's for periods of time