Portable bandsaws are invaluable on the types of sites we work. They make short work of long steel material and can be very precise. The blades will last a while if you give them a chance.
The trick is knowing where and how to cut with them. The blade on even a small bandsaw is several feet long and is being pulled in one direction only. It is this continuous dragging of teeth through the material that gives the bandsaw its speed. It is also a potential weak point if the saw is used poorly.
A bandsaw by design does not have a lot of kerf or width of cut built into the blade. So this means it is easily bound up in material. I see this mistake all the time because people try to cut in the middle of material. If you try to cut there you turn the entire piece of material into a lever and try to grab the blade. It will stop even the most powerful saw.
The way to cut with bandsaws is past a material support. This will allow the cut pieces to fall away from each other and open the gap for the blade.
If you cannot cut in this way then it is very likely that you will bind the blade up and bend it.
This is why bandsaws are not great demo tools. Use a jig saw or abrasive saw when you cannot control how the material was joined. Or if it was welded and likely has forces closing the cut area.