Don’t try to use a bar which is too heavy or long for you. Always keep your own height and strength level in mind when choosing the appropriate bar for you.
The pointed or chisel end of a large crowbar could do significant damage to property if used irresponsibly. Don’t start using a large crowbar until you are sure of what you want to do, and where you want to do it.
Work at a slow and steady pace. This is especially important during work which involves breaking through heavy materials; over-exerting yourself too soon will result in the job taking longer overall.
Bars should not be used for extremely heavy-duty work. Know your tool’s limits, or you run the risk of bending or breaking it.