If you think about it, it’s obvious: the best way to prevent tendon pain is to keep it from happening in the first place.
Every tendon problem that occurs is caused by something being wrong in your body. It might be something general, like too much systemic inflammation, which can (and probably will) eventually cause tendonitis. It might be a particular faulty movement pattern, which could lead to tendonosis. In the first case, correcting your diet will go a long way toward preventing the problem. In the second scenario, paying a professional to look at your exercise form is money well-spent. An ounce of prevention really is worth a pound of cure.
I obviously can’t make recommendations for everyone, but one of the prime areas for developing tendon problems is the shoulders. And a lot of shoulder problems could be avoided by making sure to stretch in the correct way on a regular basis. Here’s one of Joe DeFranco’s videos, which shows six different stretches that will keep your shoulders healthy and your tendons strong. Do yourself a favor and take seven minutes out of your day to watch it. It could be seven minutes that prevent you from losing months down the road.