Being prepared for the worst has to do with the inherent nature of trees. A lot of what we sell has a stamp on it, to show how it is rated. A carabiner, for example, has a mark on it that says what its rated tensile strength is when new.
Trees don’t come with stamps and are therefore inherently unsafe. The best you can do is minimize the risk as much as you can.
The best two pieces of advice? Think about what you are doing before you do it. And remember that most accidents occur late in the day, when you are tired.
Use your equipment to reduce fatigue. For example, implement a hitch advancing micro pulley beneath your climbing hitch or use a Pantin Foot Ascender to make the work less physically demanding.
At the end of the day, you will be less tired – and therefore less likely to have an accident.