Spot messengers don’t work in Svalbard, don’t rely on these in case of emergency. However, DeLorme inReach devices work fine since they are based on Iridium network. Field tested.
Be aware that even ordinary wounds take longer to heal. Be extra careful and make sure you have a well prepared first aid kit.
Walking in wellies (knee-length waterproof boots) is highly recommended. The terrain is quite treacherous, with tundra sucking you in when not expected and plenty of little streams you need to cross now and then. However, wellies tend to have very soft soles and on a rocky terrain it won’t feel comfortable. The solution is to put at least three layers of insoles made of a hard material.
Polar bears might be dangerous, but they are not that easy to encounter in July and the best is that they don’t fly around trying to peck at your head or drop an excrement bomb. Yes, the most annoying thing in Svalbard are birds. Always carry a stick with you, and if you have trekking poles (which you should have anyway) keep them up in the air. Birds will attack these instead of your head.