Before buying any cheap plasma cutter, you should know that the unit can be useful unless you choose any non-recommended brand. Also, it is important to understand that purchasing eye-candy products don’t guarantee longevity or quality results.
Again, the entire scenario depends on the model you’re choosing. There are times when even inexpensive equipment would work for years in contrast with expensive machines.
However, as everything has its limitations; therefore, after getting a low-priced tool, try your best to operate it as suggested by the manufacturers. For example, if you are warned to put the machine at rest after using it for a few hours, follow the advice. Otherwise, the overload could burn the internal mechanism.
Likewise, avoid cutting or welding non-supportive metals and never cross the max thickness level. And in case there’s a need to do that, then it’s suitable to get a model that goes with your cause.
Nevertheless, there’s no perfect parameter to evaluate the reliability. But through your experience and machine’s performance, you can identify how well, or threatening the machine would be in the long run.
Usually, cheap plasma cutting tools come with no major faults. In general, if it has completed a few tasks, then chances are that it won’t trouble for years. So, you can see the instructions and start working immediately. But we would also suggest to keep the unit clean and tidy and protect it from extreme weather conditions to save the exterior from getting caught by rust.