Placement Matters
The placement of trampolines has the potential to create some real problems for your jumpers and can be the reason behind serious injuries. Take a few minutes to carefully consider where you're going to put your trampoline before you make the purchase, then take time to fully prepare the spot before the first jumper hits the mat.
Make it level - Trampolines need to be almost perfectly level for several reasons. The most important is that your jumpers can move the trampoline if the mat isn't level. Even with anchors, this can be a problem if the jumper is hitting the mat at an angle. Jumpers may also have a tendency to bounce off the side of the trampolines if the equipment is sloped.
Overhead - Don't underestimate how high your kids will be able to jump. A motivated child can set world records. A playmate or sibling daring him to touch an overhead power line may be all the motivation your child needs to cause serious injury to himself. Tell them to never try to grab anything above them, but eliminating the possibility is the safest measure you can take.
Nearby buildings and platforms - This is especially important if you have daredevils in the family (or even in the neighborhood). While an adult might see the potential for serious injury by jumping from the roof of a shed onto the trampoline, a child with a bit of imagination might see it as a great adventure. Be sure there's nothing nearby that can encourage that behavior and use anchors so that the kids can't move the trampoline somewhere more conducive to a flying leap from a small building.
Security - A fenced area is probably a good idea, especially if you live in a neighborhood that has other children. Just as you're liable for a pool, you're liable for accidents that occur on your trampoline.
Near the house - The first instinct when choosing a place for your new trampoline is to put it far enough from the house that the squeals of delight of your little jumpers won't be too loud for those inside. However, having it close to the house means that you'll be more likely to know if someone is jumping unsupervised or if you have uninvited jumpers. You'll also be able to tell if your older jumpers are yelling for joy or if someone is in need of help.
You may find that you simply don't have an appropriate place for a trampoline. In that case, it might be best to look for some alternative piece of equipment for your children to play on.