Owning a trampoline is like owning a car.  You have to take care if it likes an investment.  When the trampoline isn’t in use for several months, such as during the winter months, it is best to store the soft parts of the trampoline indoors.  Remove the jumping mat, springs, spring pad and enclosure and store them indoors.  Severe weather conditions damage the soft parts.
Since UV rays can be strong during the summer months, UV protectant spray should applied to the spring pad and net enclosure sleeves.  UV protectant can be purchased at any auto parts store, such as Pep Boy or Kragens Auto Parts.  Quality spring pads are normally made of PVC material, which is a form of plastic.  Lower quality spring pads are made of PE, which is like a tarp.  PVC material is much stronger and thicker.  Depending on heat intensity and regularity UV protectant applied, PVC can last as short as 1 year or as long as 4-5 years.  PE material, if not taken care of properly will last about 6 months.  If taken care of properly, can last as long as 2 years.  Many companies don’t specify spring pad material, so make sure to ask your trampoline sales person.
As for the frame, try to avoid pushing or repositioning the frame.  Especially if the frame has a 1.5 mm thickness, it can and will crack at the joint and/or warp at the center.  Frame should be no less than 2.0 mm thick.  Always consider t-joints, as t-joints make the trampoline stronger and sturdier.  When cutting grass underneath the trampoline, use a trimmer.  Pushing the trampoline will stress the integrity of the t-joint.  If the trampoline is going to be moved, have at least 4 persons to lift the trampoline off the ground and reposition.  Trampoline, depending on the size and frame thickness, can be very heavy.
When jumping on the trampoline, avoid jumping more than 1 person at a time.  Multiple persons jumping at the same can increase the chances of accidents and injuries.  Injuries could be from collision, one jumping losing control and accidently landing on the order jumpers legs or arms, etc.
As for the safety net, try to avoid jumping or rebounding against the safety net.  The sole purpose of a safety net is for safety.  During the winter months, remove the safety net and store indoors.  Taking proper care of a safety net can last 2-4 years. 
That’s why it’s always important to do your research before purchasing.  Always go with the thickest frames. Ideally 2.0mm or thicker.  Make sure to get t-joints.  T-joint trampolines have more integrity than welded joints.  Don’t settle for PE material spring pads.  Go with PVC.  Happy jumping and be sure to take proper care of your trampoline.
Never wear shoes or carry sharp objects while jumping.  Sharp objects can also lead to injuries.  It can also result in cutting the jumping mat.  Never wear shoes, because might have little rocks at the bottom, which can also cut the jumping mat.