Yes, the frame is the most important part of the trampoline.  The thicker the frame, the more weight that trampoline can endure and the durability that that trampoline will withstand over the years.  A basic trampoline comes with a frame thickness of 1.2mm.  Most companies that do not display their frame thickness will most likely carry the 1.2mm thick frame.  A quality round trampoline that you can use for years has to have a frame at least 1.5 to 1.8mm.  However, a quality rectangular trampoline should have a frame that’s at least 2.5mm thick.  A frame less than 2.5mm thick on a rectangular trampoline will eventually cave-in towards the center with excessive usage.